GHSA-7gw9-cf7v-778f CVE-2026-41312 PYSEC-2026-3011
pypdf: Manipulated FlateDecode predictor parameters can exhaust RAM
- Severity
- 0.0 / 10
- Medium · CVSS 4.0
- Exploit chance (EPSS)
- 0.23%
- Chance of exploitation in the next 30 days. Higher than 13.41% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- CWE-789 Memory Allocation with Excessive Size Value
- Fix
6.10.2- Upgrade pypdf to this version or later
Description
Impact
An attacker who uses this vulnerability can craft a PDF which leads to the RAM being exhausted. This requires accessing a stream compressed using /FlateDecode with a /Predictor unequal 1 and large predictor parameters.
Patches
This has been fixed in pypdf==6.10.2.
Workarounds
If you cannot upgrade yet, consider applying the changes from PR #3734.
Affected versions
PyPI
| Package | Vulnerable | Fixed in |
|---|---|---|
| pypdf | < 6.10.2 |
6.10.2 |
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 → 6.10.2
- pip
pip install --upgrade "pypdf>=6.10.2"- poetry
poetry add "pypdf>=6.10.2"- uv
uv add "pypdf>=6.10.2"
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:H/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)
- High
- Confidentiality (subsequent systems)
- None
- Integrity (subsequent systems)
- None
- Availability (subsequent systems)
- None
CVSS 3.1 6.5
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Weakness
CWE-789: Memory Allocation with Excessive Size Value
The product allocates memory based on an untrusted, large size value, but it does not ensure that the size is within expected limits, allowing arbitrary amounts of memory to be allocated.
How to prevent it
- Implementation, Architecture and Design: Perform adequate input validation against any value that influences the amount of memory that is allocated. Define an appropriate strategy for handling requests that exceed the limit, and consider supporting a configuration option so that the administrator can extend the amount of memory to be used if necessary.
- Operation: Run your program using system-provided resource limits for memory. This might still cause the program to crash or exit, but the impact to the rest of the system will be minimized.
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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