CVE-2020-26682: In libass 0.14.0, the `ass_outline_construct`'s call to `outline_stroke` causes a signed integer overflow.

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HIGH 8.8DOWNGRADE

CVE-2020-26682 is a high-severity flaw (CVSS 8.8) affecting libass. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

In libass 0.14.0, the `ass_outline_construct`'s call to `outline_stroke` causes a signed integer overflow.

Why this priority

High severity
Public exploit reference

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

Risk facts

CVSS score	8.8 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	1.8% (top 22%)
CISA exploited list	No
Weakness	CWE-190
Published	2020-10-16
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: libass project

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

Am I affected?

Timeline

2020-10-16 14:15 UTCPublished CVE record published
2026-06-17 03:08 UTCUpdated Record last modified

libass project libass DOWNGRADE

Affected: 0.14.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 0.14.0

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 0.14.0 (Debian / Ubuntu)

apt-cache madison libass sudo apt install libass=<VERSION_BEFORE_0.14.0> sudo apt-mark hold libass

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

dnf --showduplicates list libass sudo dnf downgrade libass-<VERSION_BEFORE_0.14.0> sudo dnf versionlock add libass

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-2020-26682?

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

Is CVE-2020-26682 being exploited?

CVE-2020-26682 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-2020-26682 affect?

CVE-2020-26682 affects libass. Severity is high (CVSS 8.8). In libass 0.14.0, the `ass_outline_construct`'s call to `outline_stroke` causes a signed integer overflow.

How urgent is CVE-2020-26682?

Priority 55/100. High severity; Public exploit reference

Related CVEs

CVE-2020-36430 HIGH 7.8 UPGRADE MITIGATE libass 0.15.x before 0.15.1 has a heap-based buffer overflow in decode_chars (called from decode_font and proc
CVE-2020-24994 HIGH 8.8 UPGRADE Stack overflow in the parse_tag function in libass/ass_parse.c in libass before 0.15.0 allows remote attackers
CVE-2016-7972 HIGH 7.5 MITIGATE MITIGATE The check_allocations function in libass/ass_shaper.c in libass before 0.13.4 allows remote attackers to cause
CVE-2016-7970 HIGH 7.5 MITIGATE UPGRADE Buffer overflow in the calc_coeff function in libass/ass_blur.c in libass before 0.13.4 allows remote attacker
CVE-2016-7969 HIGH 7.5 MITIGATE MITIGATE The wrap_lines_smart function in ass_render.c in libass before 0.13.4 allows remote attackers to cause a denia

References

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