GHSA-763m-79hh-57f2 CVE-2026-84311 PYSEC-2026-3911
pypdf: Possible long runtimes/large memory usage when extracting XForm objects
- Severity
- 0.0 / 10
- Low · CVSS 4.0
- Exploit chance (EPSS)
- 0.14%
- Chance of exploitation in the next 30 days. Higher than 2.93% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- CWE-834 Excessive Iteration
- Fix
6.16.1- Upgrade pypdf to this version or later
Description
Impact
An attacker who uses this vulnerability can craft a PDF which leads to long runtimes and large memory consumption. This requires extracting the text of a page with lots of XForm objects, where some of them might be re-used.
Patches
This has been fixed in pypdf==6.16.1.
Workarounds
If you cannot upgrade yet, consider applying the changes from PR #3966.
Affected versions
PyPI
| Package | Vulnerable | Fixed in |
|---|---|---|
| pypdf | < 6.16.1 |
6.16.1 |
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.
pypdf PyPI → 6.16.1
- pip
pip install --upgrade "pypdf>=6.16.1"- poetry
poetry add "pypdf>=6.16.1"- uv
uv add "pypdf>=6.16.1"
Severity breakdown
CVSS 4.0 0.0
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
- Attack vector
- Local
- Attack complexity
- Low
- Attack requirements
- None
- Privileges required
- None
- User interaction
- Passive
- Confidentiality (vulnerable system)
- None
- Integrity (vulnerable system)
- None
- Availability (vulnerable system)
- Low
- Confidentiality (subsequent systems)
- None
- Integrity (subsequent systems)
- None
- Availability (subsequent systems)
- None
CVSS 3.1 3.3
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L
- Attack vector
- Local
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- Low
Weakness
CWE-834: Excessive Iteration
The product performs an iteration or loop without sufficiently limiting the number of times that the loop is executed.
References
Advisories
Packages
Other links
Timeline
- Published
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| GHSA-5849-834g-hvw5 pypdf has possible infinite loop when hitting EOF in standard xref table during trailer search | High | Also affects pypdf |
| GHSA-cggf-277g-3q54 pypdf has possible large memory usage when parsing page tree | High | Also affects pypdf |
| GHSA-mfr5-77xh-9j7h pypdf has possible infinite loop when cloning dictionaries | High | Also affects pypdf |
| GHSA-42gh-23hr-vphw pypdf has possible long runtimes when retrieving page labels | High | Also affects pypdf |
| GHSA-4vqv-7265-gm2w pypdf has possible large memory usage for exceptions in strict mode | High | Also affects pypdf |
| GHSA-62m5-6wh8-28x7 pypdf has possible long runtimes/large memory usage for encrypted PDF files | High | Also affects pypdf |
| GHSA-x3rh-gjgm-fmqc pypdf has possible large memory usage when parsing cross-reference streams | High | Also affects pypdf |
| GHSA-jr96-gvgh-j3r4 pypdf: Possible long runtimes for repeated malformed cross-reference entries (Follow-up) | High | Also affects pypdf |
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