CVE-2026-81869OpenTelemetry-Go: UTF-8 replacement rune bypasses attribute length truncation
Updated under an hour ago ()
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It affects open-telemetry opentelemetry-go. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
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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.
- CVSS
- 5.1 MEDIUM (v4.0, CNA)CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
- Weakness (CWE)
- CWE-176, CWE-400
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- GitHub_M
- NVD analysis
- Awaiting Analysis
- Record last updated
- Sep 17, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
open-telemetry opentelemetry-go open_telemetry:opentelemetry_go (from the name) | from 1.10.0, < 1.33.0 | CNA record |
References
- https://github.com/open-telemetry/opentelemetry-go/security/advisories/GHSA-p9f8-wvj8-2fg8x-refsource-confirm
- https://github.com/open-telemetry/opentelemetry-go/issues/5996x-refsource-misc
- https://github.com/open-telemetry/opentelemetry-go/pull/5997x-refsource-misc
- https://github.com/open-telemetry/opentelemetry-go/commit/e016a78c9f5b24a1c2beeaad47686c2f2213f49ax-refsource-misc
- https://github.com/open-telemetry/opentelemetry-go/releases/tag/sdk/v1.33.0x-refsource-misc
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.