Machine-written summary
Summary written by Claude Haiku from the source advisory. Not reviewed by a person.
The opentelemetry-api package for PyPI, versions before 1.45.1, parses inbound W3C tracestate headers with a regular expression whose cost grows quadratically with long runs of spaces or tabs, so a single unauthenticated request carrying a tracestate header of about 100 KB can occupy the processing worker for several seconds. Exposure depends on whether the HTTP server accepts such large headers, and under an asyncio server other connections can be delayed while it runs. Upgrade opentelemetry-api to 1.45.1 or later; as a workaround, enforce request header size limits at the server or gateway.
Not analysed yet
We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.
Severity and exploitation
| Score | Rating | CVSS | Vector | Source |
|---|---|---|---|---|
| 5.3 | Medium | 3.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L | CNA (GitHub_M) |
- CISA KEV Not listed.
- EPSS 0.0049, the 42nd percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.
Timeline
- 31 Oct 2026, 14:08 UTC First seen by agentprime
- 31 Oct 2026, 14:08 UTC Confirmed by OSV
Sources
- GitHub Advisory Database: GHSA-xcq7-p3pf-p88h
- OSV: GHSA-xcq7-p3pf-p88h
- github.com/open-telemetry/opentelemetry-python/security/advisories/GHSA-xcq7-p3pf-p88h
- github.com/open-telemetry/opentelemetry-python/pull/5749
- github.com/open-telemetry/opentelemetry-python/commit/d5224bf4ffdf2aee1b592ad238dcc32ca957f26b
- github.com/open-telemetry/opentelemetry-python
- github.com/open-telemetry/opentelemetry-python/blob/main/CHANGELOG.md#version-1451066b1-2026-10-06
- github.com/open-telemetry/opentelemetry-python/releases/tag/v1.45.1