CVE-2026-102270.

Disclosure summary

### Summary There is a Re-DoS vulnerability in the `is_pem_format` function which results in a intesive CPU usage if an attacker is been able to provide a custom certificate. ### Details The problem is that the lazy quantifier `.+?` will always first try to match as little as possible until it finds a `---- END`. Normally this means the complexity of this should be O(N). However, by providing an input which consists only of `----BEGIN CERTIFICATE-----` lines and no `---- END` line, the regex algorithm will first try to match the first line and then, with the lazy quantifier, all the lines until the end O(N), which then fails since it is unable to find a `---- END` line. It will then jump to the next line, resulting in N re-scans of the whole string, which means the complexity basically results in O(N²). ### PoC ```python import time import re BEGIN_LINE = b"-----BEGIN CERTIFICATE-----\n" _PEMS = { b"CERTIFICATE", b"TRUSTED CERTIFICATE", b"PRIVATE KEY", b"PUBLIC KEY", b"ENCRYPTED PRIVATE KEY", b"OPENSSH PRIVATE KEY", b"DSA PRIVATE KEY", b"RSA PRIVATE KEY", b"RSA PUBLIC KEY", b"EC PRIVATE KEY", b"DH PARAMETERS", b"NEW CERTIFICATE REQUEST", b"CERTIFICATE REQUEST", b"SSH2 PUBLIC KEY",

Source-specific records & product guidance

Sources retain their own attribution and scoring. Follow the original record to confirm affected versions, fixed releases, and configuration conditions.

Original records & references

• NIST NVD record
• CVE Program record
• github.com — Reviewed advisory

PUBLISHED 2026-09-30T10:40:25-04:00
MODIFIED 2026-09-30T10:40:26-04:00
INGESTED 2026-10-06T11:43:09-04:00