What is CVE-2025-66866?

CVE-2025-66866 is a high-severity vulnerability in GNU Binutils, classified under Improper Input Validation. CVSS score: 7.5/10. Published 2025-12-29.

How severe is CVE-2025-66866?

High severity. CVSS v3 base score is 7.5 out of 10.

Improper input validation in GNU Binutils

CVE-2025-66866

An issue was discovered in function d_abi_tags in file cp-demangle.c in BinUtils 2.26 allows attackers to cause a denial of service via crafted PE file.

Vulnerability class: Drupalgeddon 2 (CVE-2018-7600)

Published 2025-12-29 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.003 (21.5th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 22nd percentile — 21.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: -0.000

Affected products

GNU Binutils — versions 2.26

Weakness classification (CWE)

CWE-20 — Improper Input Validation

References

github.com/caozhzh/CRGF-Vul/blob/main/cxxfilt/crash6.md (Exploit, Third Party Advisory)

Frequently asked questions

What is CVE-2025-66866?: CVE-2025-66866 is a high-severity vulnerability in GNU Binutils, classified under Improper Input Validation. CVSS score: 7.5/10. Published 2025-12-29.
How severe is CVE-2025-66866?: High severity. CVSS v3 base score is 7.5 out of 10.