CVE-2017-13666: An integer underflow vulnerability exists in pixel-a.asm, the x86 assembly code for planeClipAndMax() in Multi

Routine

MEDIUM 5.5DOWNGRADE

CVE-2017-13666 is a medium-severity flaw (CVSS 5.5) affecting x265. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

An integer underflow vulnerability exists in pixel-a.asm, the x86 assembly code for planeClipAndMax() in MulticoreWare x265 through 2.5, as used in libbpg and other products. A small height value can cause an integer underflow, which leads to a crash. This is a different vulnerability than CVE-2017-8906.

Why this priority

Public exploit reference

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

Risk facts

CVSS score	5.5 (Medium)
Attack vector	Local
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.4% (top 68%)
CISA exploited list	No
Weakness	CWE-191
Published	2017-08-24
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: multicorewareinc

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

Am I affected?

Timeline

2017-08-24 06:29 UTCPublished CVE record published
2026-06-17 01:04 UTCUpdated Record last modified

multicorewareinc x265 DOWNGRADE

Affected: 0.1 · 0.2 · 0.3 · 0.4 · 0.4.1 · 0.5 · 0.6 · 0.7

Fixed in: no fixed release known

Safe to downgrade to: a release before 0.1

1. Check installed version

apt-cache policy x265 || rpm -q x265 || x265 --version

2. No fixed release: DOWNGRADE to a release before 0.1 (Debian / Ubuntu)

apt-cache madison x265 sudo apt install x265=<VERSION_BEFORE_0.1> sudo apt-mark hold x265

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

dnf --showduplicates list x265 sudo dnf downgrade x265-<VERSION_BEFORE_0.1> sudo dnf versionlock add x265

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-2017-13666?

x265: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2017-13666 being exploited?

CVE-2017-13666 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-2017-13666 affect?

CVE-2017-13666 affects x265. Severity is medium (CVSS 5.5). An integer underflow vulnerability exists in pixel-a.asm, the x86 assembly code for planeClipAndMax() in MulticoreWare x265 through 2.5, as used in libbpg and other products. A small height value can cause an integer underflow, which leads

How urgent is CVE-2017-13666?

Priority 32/100. Public exploit reference

References

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