CVE-2026-115585High· 7.1▾ Twilightpypdf: Possible long runtimes for repeated malformed cross-reference entries (Follow-up)
▾ Twilight zone — High severity, or a signal on a lesser flaw
impact 39.1 · likelihood 0 · exploitation 0
Need a working PoC? Pro members can cast a request and our team develops one — it lands right here.
An attacker who uses this vulnerability can craft a PDF which leads to long runtimes. This requires cross-reference streams with repeated malformed cross-reference streams.
This has been fixed in pypdf==6.21.2.
If you cannot upgrade yet, consider applying the changes from PR #4240.
This is a follow-up to https://github.com/py-pdf/pypdf/security/advisories/GHSA-55h5-xmcq-c37v, which had the side-effect of still loading the whole stream again despite the cache being present.
pypdf < 6.21.2Upgrade to a patched release:
pypdf 6.21.2Connected by shared product, vendor, weakness, or advisory.
CVE-2026-115572High· 7.1pypdf: Possible long runtimes for repeated references to the same missing object
CVE-2026-113789Medium· 6.0pypdf: Possible long runtimes/large memory usage when retrieving form fields
CVE-2026-102999High· 7.5pypdf is a free and open-source pure-python PDF library
CVE-2026-102997High· 7.5pypdf is a free and open-source pure-python PDF library
CVE-2026-102994High· 7.5pypdf is a free and open-source pure-python PDF library
CVE-2026-115580High· 7.1pypdf: Possible long runtimes for large xref table header limits