GHSA-23w6-3w8w-8484 CVE-2026-84310 PYSEC-2026-3910
pypdf: Possible long runtimes/large memory usage when retrieving outlines
- 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
- 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 accessing the outlines of a document with either lots of entries or nested outlines with long re-used nesting paths.
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-405: Asymmetric Resource Consumption (Amplification)
The product does not properly control situations in which an adversary can cause the product to consume or produce excessive resources without requiring the adversary to invest equivalent work or otherwise prove authorization, i.e., the adversary's influence is "asymmetric."
How to prevent it
- Architecture and Design: An application must make resources available to a client commensurate with the client's access level.
- Architecture and Design: An application must, at all times, keep track of allocated resources and meter their usage appropriately.
- System Configuration: Consider disabling resource-intensive algorithms on the server side, such as Diffie-Hellman key exchange.
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 |
MergeHarbor checks every repository's dependencies against this database, ranks what matters by exploitability and reachability, routes it to the owning team and opens the fix pull request.
Check your repos with MergeHarbor