CVE-2023-36807: pypdf is a pure-python PDF library capable of splitting, merging, cropping, and transforming the pages of PDF

Routine

MEDIUM 6.2DOWNGRADE

CVE-2023-36807 is a medium-severity flaw (CVSS 6.2) affecting pypdf. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

pypdf is a pure-python PDF library capable of splitting, merging, cropping, and transforming the pages of PDF files. In version 2.10.5 an attacker who uses this vulnerability can craft a PDF which leads to an infinite loop. This infinite loop blocks the current process and can utilize a single core of the CPU by 100%. It does not affect memory usage. That is, for example, the case if the user extracted metadata from such a malformed PDF. Versions

Why this priority

Public exploit reference

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	6.2 (Medium)
Attack vector	Local
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.6% (top 53%)
CISA exploited list	No
Weakness	CWE-835
Published	2023-06-30
Last modified	2026-11-02

Publisher (CNA): GitHub, Inc. · Vendor: py-pdf

Last updated 2026-11-02 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2023-06-30 19:15 UTCPublished CVE record published
2026-11-02 16:06 UTCUpdated Record last modified

py-pdf pypdf DOWNGRADE

Affected: 2.10.5

Fixed in: no fixed release known

Safe to downgrade to: a release before 2.10.5

1. Check installed version

apt-cache policy pypdf || rpm -q pypdf || pypdf --version

2. No fixed release: DOWNGRADE to a release before 2.10.5 (Debian / Ubuntu)

apt-cache madison pypdf sudo apt install pypdf=<VERSION_BEFORE_2.10.5> sudo apt-mark hold pypdf

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list pypdf sudo dnf downgrade pypdf-<VERSION_BEFORE_2.10.5> sudo dnf versionlock add pypdf

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2023-36807?

pypdf: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2023-36807 being exploited?

CVE-2023-36807 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2023-36807 affect?

CVE-2023-36807 affects pypdf. Severity is medium (CVSS 6.2). pypdf is a pure-python PDF library capable of splitting, merging, cropping, and transforming the pages of PDF files. In version 2.10.5 an attacker who uses this vulnerability can craft a PDF which leads to an infinite loop. This infinite lo

How urgent is CVE-2023-36807?

Priority 39/100. Public exploit reference

Software pages

Python vulnerabilities

Related CVEs

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References

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