CVE-2026-81869

Name	CVE-2026-81869
Description	OpenTelemetry-Go is the Go implementation of OpenTelemetry. From version 1.10.0 until 1.33.0, the sdk/trace/span.go attribute truncation path can fail to enforce AttributeValueLengthLimit for string and string-slice attributes containing the valid Unicode replacement character U+FFFD. safeTruncateValidUTF8 treats the valid replacement rune as invalid UTF-8 and returns the original input, while strings.ToValidUTF8 leaves that valid rune unchanged, so a second safeTruncate attempt can also return the oversized value. An attacker who controls span attribute content can retain values longer than the configured limit, increasing per-span memory use and weakening denial-of-service protection in the instrumented process. This issue is fixed in version 1.33.0.
Source	CVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
golang-opentelemetry-otel (PTS)	bookworm	1.1.0-2	fixed
	trixie	1.31.0-4	vulnerable
	forky, sid	1.46.0-2	fixed

The information below is based on the following data on fixed versions.

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
golang-opentelemetry-otel	source	bookworm	(not affected)
golang-opentelemetry-otel	source	(unstable)	1.43.0-1

Notes

[trixie] - golang-opentelemetry-otel <no-dsa> (Minor issue)
[bookworm] - golang-opentelemetry-otel <not-affected> (Vulnerable code introduced in 1.10.0)
https://github.com/open-telemetry/opentelemetry-go/security/advisories/GHSA-p9f8-wvj8-2fg8
https://github.com/open-telemetry/opentelemetry-go/issues/5996
https://github.com/open-telemetry/opentelemetry-go/pull/5997
Introduced with: https://github.com/open-telemetry/opentelemetry-go/commit/49a653682f1257a66771324e818f6a83fb13d62b (v1.10.0)
Fixed by: https://github.com/open-telemetry/opentelemetry-go/commit/e016a78c9f5b24a1c2beeaad47686c2f2213f49a (v1.33.0)