GHSA-m449-cwjh-6pw7

Suggest an improvement
Source
https://github.com/advisories/GHSA-m449-cwjh-6pw7
Import Source
https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2025/11/GHSA-m449-cwjh-6pw7/GHSA-m449-cwjh-6pw7.json
JSON Data
https://api.osv.dev/v1/vulns/GHSA-m449-cwjh-6pw7
Aliases
Downstream
CGA (3)
Published
2025-11-24T22:42:07Z
Modified
2026-09-10T03:50:31Z
Severity
  • 6.6 (Medium) CVSS_V4 - 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/E:U CVSS Calculator
Summary
pypdf's LZWDecode streams be manipulated to exhaust RAM
Details

Impact

An attacker who uses this vulnerability can craft a PDF which leads to a memory usage of up to 1 GB per stream. This requires parsing the content stream of a page using the LZWDecode filter.

This is a follow up to GHSA-jfx9-29x2-rv3j to align the default limit with the one for zlib.

Patches

This has been fixed in pypdf==6.4.0.

Workarounds

If users cannot upgrade yet, use the line below to overwrite the default in their code:

pypdf.filters.LZW_MAX_OUTPUT_LENGTH = 75_000_000
Database specific 
{
    "cwe_ids":  [
        "CWE-400",
        "CWE-409"
    ],
    "github_reviewed":  true,
    "github_reviewed_at":  "2025-11-24T22:42:07Z",
    "nvd_published_at":  "2025-11-26T00:15:51Z",
    "severity":  "MODERATE"
}
References

Affected packages

PyPI / pypdf

Package

Name
pypdf
View open source insights on deps.dev
Purl
pkg:pypi/pypdf

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected
Fixed
6.4.0

Affected versions

1.*
1.0
1.1
1.2
1.3
1.4
1.5
1.6
1.7
1.8
1.9
1.10
1.11
1.12
1.13
3.*
3.1.0
3.2.0
3.2.1
3.3.0
3.4.0
3.4.1
3.5.0
3.5.1
3.5.2
3.6.0
3.7.0
3.7.1
3.8.0
3.8.1
3.9.0
3.9.1
3.10.0
3.11.0
3.11.1
3.12.0
3.12.1
3.12.2
3.13.0
3.14.0
3.15.0
3.15.1
3.15.2
3.15.3
3.15.4
3.15.5
3.16.0
3.16.1
3.16.2
3.16.3
3.16.4
3.17.0
3.17.1
3.17.2
3.17.3
3.17.4
4.*
4.0.0
4.0.1
4.0.2
4.1.0
4.2.0
4.3.0
4.3.1
5.*
5.0.0
5.0.1
5.1.0
5.2.0
5.3.0
5.3.1
5.4.0
5.5.0
5.6.0
5.6.1
5.7.0
5.8.0
5.9.0
6.*
6.0.0
6.1.0
6.1.1
6.1.2
6.1.3
6.2.0
6.3.0

Database specific

source 
"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2025/11/GHSA-m449-cwjh-6pw7/GHSA-m449-cwjh-6pw7.json"