CVE-2026-33123
published 2026-03-20CVE-2026-33123: pypdf is a free and open-source pure-python PDF library. Versions prior to 6.9.1 allow an attacker to craft a malicious PDF which leads to long runtimes and/or…
PriorityP432medium6.5CVSS 3.1
AVNACLPRNUIRSUCNINAH
EPSS
0.35%
26.8th percentile
pypdf is a free and open-source pure-python PDF library. Versions prior to 6.9.1 allow an attacker to craft a malicious PDF which leads to long runtimes and/or large memory usage. Exploitation requires accessing an array-based stream with many entries. This issue has been fixed in version 6.9.1.
Affected
6 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| debian | pypdf | < pypdf 6.9.2-1 (forky) | pypdf 6.9.2-1 (forky) |
| debian | pypdf2 | < pypdf 6.9.2-1 (forky) | pypdf 6.9.2-1 (forky) |
| py-pdf | pypdf | < 6.9.1 | 6.9.1 |
| pypdf_project | pypdf | < 6.9.1 | 6.9.1 |
| pypdf_project | pypdf | >= 0 < 6.9.2-1 | 6.9.2-1 |
| pypdf_project | pypdf | >= 0 < 6.9.1 | 6.9.1 |
CVSS provenance
nvdv3.16.5MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
nvdv4.05.1MEDIUMCVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
osv5.1MEDIUM
vendor_debian5.1MEDIUM
vendor_redhat5.1MEDIUM
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OSV
CVE-2026-33123: pypdf is a free and open-source pure-python PDF library
osv·2026-03-20·CVSS 5.1
CVE-2026-33123 [MEDIUM] CVE-2026-33123: pypdf is a free and open-source pure-python PDF library
pypdf is a free and open-source pure-python PDF library. Versions prior to 6.9.1 allow an attacker to craft a malicious PDF which leads to long runtimes and/or large memory usage. Exploitation requires accessing an array-based stream with many entries. This issue has been fixed in version 6.9.1.
OSV
pypdf has inefficient decoding of array-based streams
osv·2026-03-18
CVE-2026-33123 [MEDIUM] pypdf has inefficient decoding of array-based streams
pypdf has inefficient decoding of array-based streams
### Impact
An attacker who uses this vulnerability can craft a PDF which leads to long runtimes and/or large memory usage. This requires accessing an array-based stream with lots of entries.
### Patches
This has been fixed in [pypdf==6.9.1](https://github.com/py-pdf/pypdf/releases/tag/6.9.1).
### Workarounds
If you cannot upgrade yet, consider applying the changes from PR [#3686](https://github.com/py-pdf/pypdf/pull/3686).
GHSA
pypdf has inefficient decoding of array-based streams
ghsa·2026-03-18
CVE-2026-33123 [MEDIUM] CWE-400 pypdf has inefficient decoding of array-based streams
pypdf has inefficient decoding of array-based streams
### Impact
An attacker who uses this vulnerability can craft a PDF which leads to long runtimes and/or large memory usage. This requires accessing an array-based stream with lots of entries.
### Patches
This has been fixed in [pypdf==6.9.1](https://github.com/py-pdf/pypdf/releases/tag/6.9.1).
### Workarounds
If you cannot upgrade yet, consider applying the changes from PR [#3686](https://github.com/py-pdf/pypdf/pull/3686).
Red Hat
pypdf: pypdf: Denial of Service due to excessive resource consumption from crafted PDF
vendor_redhat·2026-03-20·CVSS 5.1
CVE-2026-33123 [MEDIUM] CWE-770 pypdf: pypdf: Denial of Service due to excessive resource consumption from crafted PDF
pypdf: pypdf: Denial of Service due to excessive resource consumption from crafted PDF
pypdf is a free and open-source pure-python PDF library. Versions prior to 6.9.1 allow an attacker to craft a malicious PDF which leads to long runtimes and/or large memory usage. Exploitation requires accessing an array-based stream with many entries. This issue has been fixed in version 6.9.1.
A flaw was found in pypdf, a pure-python PDF library. An attacker can craft a malicious PDF file that, when processed, leads to excessive resource consumption, causing long runtimes and high memory usage. This can result in a Denial of Service (DoS) condition, making the application unresponsive or unstable.
Mitigation: Mitigation for this issue is either not available or the currently available options do not
Debian
CVE-2026-33123: pypdf - pypdf is a free and open-source pure-python PDF library. Versions prior to 6.9.1...
vendor_debian·2026·CVSS 5.1
CVE-2026-33123 [MEDIUM] CVE-2026-33123: pypdf - pypdf is a free and open-source pure-python PDF library. Versions prior to 6.9.1...
pypdf is a free and open-source pure-python PDF library. Versions prior to 6.9.1 allow an attacker to craft a malicious PDF which leads to long runtimes and/or large memory usage. Exploitation requires accessing an array-based stream with many entries. This issue has been fixed in version 6.9.1.
Scope: local
bookworm: open
forky: resolved (fixed in 6.9.2-1)
sid: resolved (fixed in 6.9.2-1)
trixie: open
No detection rules found.
No public exploits indexed.
2026-03-20
Published