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GHSA-mvg9-xffr-p774 BIT-pillow-2021-25291 CVE-2021-25291 PYSEC-2021-37

Out of bounds read in Pillow

High PyPI
Severity
0.0 / 10
High · CVSS 4.0
Exploit chance (EPSS)
1.40%
Chance of exploitation in the next 30 days. Higher than 72.45% of scored vulnerabilities.
Known exploited
No
Not in CISA's catalog
Weakness
CWE-125 Out-of-bounds Read
Fix
8.2.0
Upgrade pillow to this version or later

Description

An issue was discovered in Pillow before 8.2.0. In TiffDecode.c, there is an out-of-bounds read in TiffreadRGBATile via invalid tile boundaries.

Affected versions

PyPI

PackageVulnerableFixed in
pillow
< 8.2.0
8.2.0
pillow
< 8.1.1
8.1.1

How to fix

Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.

pillow PyPI → 8.2.0

pip
pip install --upgrade "pillow>=8.2.0"
poetry
poetry add "pillow>=8.2.0"
uv
uv add "pillow>=8.2.0"

Severity breakdown

CVSS 4.0 0.0

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

Attack vector
Network
Attack complexity
Low
Attack requirements
None
Privileges required
None
User interaction
None
Confidentiality (vulnerable system)
None
Integrity (vulnerable system)
None
Availability (vulnerable system)
High
Confidentiality (subsequent systems)
None
Integrity (subsequent systems)
None
Availability (subsequent systems)
None

CVSS 3.1 7.5

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

Weakness

CWE-125: Out-of-bounds Read

The product reads data past the end, or before the beginning, of the intended buffer.

How to prevent it
  • Implementation: Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does. When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, "boat" may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as "red" or "blue." Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code's environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright. To reduce the likelihood of introducing an out-of-bounds read, ensure that you validate and ensure correct calculations for any length argument, buffer size calculation, or offset. Be especially careful of relying on a sentinel (i.e. special character such as NUL) in untrusted inputs.
  • Architecture and Design: Use a language that provides appropriate memory abstractions.

References

Timeline

  1. Published
  2. Last updated by the source
  3. Latest EPSS score
AdvisorySeverityWhy it's related
PYSEC-2023-175
Pillow versions before v10.0.1 bundled libwebp binaries in wheels that are vulnerable to CVE-2023-5129 (previously CVE-2023-4863).
High Known exploited Also affects pillow
GHSA-j7hp-h8jx-5ppr
libwebp: OOB write in BuildHuffmanTable
High Known exploited Also affects pillow
GHSA-78g4-xqwv-q3g8
Pillow: Bundled libopenjp2 2.5.4 in all wheels since 11.1.0 carries OSV-2025-219 heap-buffer-overflow write reachable from Image.open().load()
High Also affects pillow
GHSA-654x-cwwv-5j9c
Pillow: Arrow export leaks stale heap memory when PILLOW_ALIGNMENT > 1
Medium Also affects pillow
GHSA-xvh5-g6gv-559v
Pillow: Memory disclosure and segfault in libtiff encoder via crafted TIFF tags
High Also affects pillow
GHSA-g7cr-3p24-7wf7
Pillow: Heap buffer overflow writing JPEG comment after ICC profile fills buffer
High Also affects pillow
GHSA-9v9v-9qvf-h2hj
Pillow: Heap over-read in WMF/EMF rendering via 16-bit dimension truncation (Windows builds)
High Also affects pillow
GHSA-g4qv-2jxx-769h
Pillow: PNG eXIf chunk makes EXIF parsing run in quadratic time
Medium Also affects pillow
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