GHSA-g94r-2vxg-569j: OpenTelemetry.Api (CVE-2026-40894)

Package	Ecosystem	Affected	Fixed in
OpenTelemetry.Api	NuGet	>=0.5.0-beta.2, <1.15.3	1.15.3
OpenTelemetry.Extensions.Propagators	NuGet	>=1.3.1, <1.15.3	1.15.3

Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

GHSA-g94r-2vxg-569j affects the OpenTelemetry.Api package from 0.5.0-beta.2 up to 1.15.3 and the OpenTelemetry.Extensions.Propagators package from 1.3.1 up to 1.15.3. An attacker who can send propagation headers (baggage, B3 or Jaeger) to an application that parses them can cause excessive memory allocation, a possible denial of service. Upgrade both packages to 1.15.3. Limiting HTTP request header sizes or disabling baggage or trace propagation can serve as workarounds.

Written 9 Nov 2026.

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 0.0046, the 39th percentile, on 9 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

31 Oct 2026, 15:21 UTC First seen by agentprime
31 Oct 2026, 15:21 UTC Confirmed by OSV

Sources

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.