Medium severity · published Mar 6, 2026
CVE-2026-28804
pypdf: Inefficient decoding of ASCIIHexDecode streams
5.3
CVSS
0.4%
EPSS
No
On KEV
Description
pypdf is a free and open-source pure-python PDF library. Prior to version 6.7.5, an attacker who uses this vulnerability can craft a PDF which leads to long runtimes. This requires accessing a stream which uses the /ASCIIHexDecode filter. This issue has been patched in version 6.7.5.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
Low
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 36% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
PY
pypdf · py-pdf
< 6.7.5 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-28804
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-28804
Patch
https://github.com/py-pdf/pypdf/commit/648c627d2657447dfb1773412af05a0a5103b98f
Issue Tracking
https://github.com/py-pdf/pypdf/pull/3666
Product
https://github.com/py-pdf/pypdf/releases/tag/6.7.5
Patch
https://github.com/py-pdf/pypdf/security/advisories/GHSA-9m86-7pmv-2852
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