CVE-2025-66866Public exploit

Process crash via invalid ABI-tag dereference

Published Dec 29, 2025 · Updated Dec 29, 2025

Improper input validation in GNU Binutils 2.26 allows context-dependent attackers to crash c++filt with a crafted PE file. The d_abi_tags parser in libiberty/cp-demangle.c dereferences an invalid high address while reading crafted ABI-tag data, producing a segmentation fault. Exploitation requires the victim to process the input with the affected demangler, and the observed consequence is termination of that single process.

CVSS severity7.5
High
EPSS probability0.32%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper input validation in GNU Binutils 2.26 allows context-dependent attackers to crash c++filt with a crafted PE file. The d_abi_tags parser in libiberty/cp-demangle.c dereferences an invalid high address while reading crafted ABI-tag data, producing a segmentation fault. Exploitation requires the victim to process the input with the affected demangler, and the observed consequence is termination of that single process.

The record

CVE
CVE-2025-66866
Published
Dec 29, 2025
Updated
Dec 29, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-20, T1499.004
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 29, 2025CVE publishedPublication date reported by the CVE source.
  2. Dec 29, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

5.5CISA-ADPCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
5.5UbuntuCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
7.5NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-20Improper Input Validation
T1499.004Application or System Exploitation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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