CVE-2023-26266: In AFL++ 4.05c, the CmpLog component uses the current working directory to resolve and execute unprefixed fuzz

Routine

HIGH 7.3DOWNGRADE

CVE-2023-26266 is a high-severity flaw (CVSS 7.3) affecting afl\+\+. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

In AFL++ 4.05c, the CmpLog component uses the current working directory to resolve and execute unprefixed fuzzing targets, allowing code execution.

Why this priority

High severity
Public exploit reference

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	7.3 (High)
Attack vector	Local
Attack complexity	Low
Privileges needed	Low
User interaction	Required
EPSS exploit chance	0.4% (top 66%)
CISA exploited list	No
Weakness	CWE-427
Published	2023-02-21
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: afl\+\+ project

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2023-02-21 04:15 UTCPublished CVE record published
2026-06-17 05:42 UTCUpdated Record last modified

afl\+\+ project afl\+\+ DOWNGRADE

Affected: 4.05c

Fixed in: no fixed release known

Safe to downgrade to: a release before 4.05c

1. Check installed version

apt-cache policy afl++ || rpm -q afl++ || afl++ --version

2. No fixed release: DOWNGRADE to a release before 4.05c (Debian / Ubuntu)

apt-cache madison afl++ sudo apt install afl++=<VERSION_BEFORE_4.05c> sudo apt-mark hold afl++

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list afl++ sudo dnf downgrade afl++-<VERSION_BEFORE_4.05c> sudo dnf versionlock add afl++

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2023-26266?

afl\+\+: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2023-26266 being exploited?

CVE-2023-26266 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2023-26266 affect?

CVE-2023-26266 affects afl\+\+. Severity is high (CVSS 7.3). In AFL++ 4.05c, the CmpLog component uses the current working directory to resolve and execute unprefixed fuzzing targets, allowing code execution.

How urgent is CVE-2023-26266?

Priority 39/100. High severity; Public exploit reference

References

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