CVE-2025-8736Public exploit

Process crash via unchecked lexer state index

Published Aug 8, 2025 · Updated Aug 8, 2025

Buffer overflow in GNU cflow 1.8 and earlier allows local users to crash the process by supplying a malformed C source file. The yylex lexer uses a corrupted yy_current_state value as an unchecked index into yy_accept, causing an out-of-bounds memory access. The user must be able to run cflow on attacker-controlled input; the demonstrated consequence is a segmentation fault, while broader confidentiality and integrity effects are scored but not publicly demonstrated.

CVSS severity4.8
Medium
EPSS probability0.16%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Buffer overflow in GNU cflow 1.8 and earlier allows local users to crash the process by supplying a malformed C source file. The yylex lexer uses a corrupted yy_current_state value as an unchecked index into yy_accept, causing an out-of-bounds memory access. The user must be able to run cflow on attacker-controlled input; the demonstrated consequence is a segmentation fault, while broader confidentiality and integrity effects are scored but not publicly demonstrated.

The record

CVE
CVE-2025-8736
Published
Aug 8, 2025
Updated
Aug 8, 2025
Vendor
The GnuPG Project
Product
GNU cflow
Classifications
CWE-120, T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 8, 2025CVE publishedPublication date reported by the CVE source.
  2. Aug 8, 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?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=1.0
  2. Affected versionversion=1.1
  3. Affected versionversion=1.2
  4. Affected versionversion=1.3
  5. Affected versionversion=1.4
  6. Affected versionversion=1.5
  7. Affected versionversion=1.6
  8. Affected versionversion=1.7
  9. Affected versionversion=1.8

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The GnuPG Project · GNU cflowversion=1.0; version=1.1; version=1.2; version=1.3; version=1.4; version=1.5; version=1.6; version=1.7; version=1.8

Published CVSS scores

5.3VulDB CNACVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L
4.3VulDB CNAAV:L/AC:L/Au:S/C:P/I:P/A:P
4.8VulDB CNACVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

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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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
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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