Description
pypdf is a free and open-source pure-python PDF library. Prior to 6.21.4, pypdf can enter an infinite loop while opening a crafted incomplete PDF whose standard cross-reference table reaches the end of the file without a trailer. The trailer search can repeatedly rewind to the same stream position instead of terminating when parsing makes no progress, blocking the processing thread. This issue is fixed in version 6.21.4.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| py-pdf | pypdf | < 6.21.4 | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | pypdf | 6.21.4-1 | — |
| Debian 13 | pypdf | No fix yet | — |
| Debian 12 | pypdf +1 | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | pypdf | No fix yet | — |
| Ubuntu 26.04 LTS | pypdf | No fix yet | — |
| Ubuntu 24.04 LTS | pypdf | No fix yet | — |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Leap 16.0 | python-pypdf | 6.19.0-bp160.3.1 | openSUSE-SU-2026:22219-1 |
Wolfi
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Wolfi rolling | open-webui | 0.12.3-r15 | — |
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| PyPI | pypdf | < 6.21.4 | 6.21.4 | GHSA-5849-834g-hvw5 |
Advisories 1
- openSUSE-SU-2026:22219-1 Security update for python-pypdf SUSE / openSUSE Security Updates · Nov 4, 2026