CVE-2023-1999: Use after free in libwebp

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.0% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2023-06-20 · updated 2026-06-17
Weakness: CWE-416

Description

There exists a use after free/double free in libwebp. An attacker can use the ApplyFiltersAndEncode() function and loop through to free best.bw and assign best = trial pointer. The second loop will then return 0 because of an Out of memory error in VP8 encoder, the pointer is still assigned to trial and the AddressSanitizer will attempt a double free.

Affected products

Chromium libwebp: from 0.4.2 before 1.3.1 — fixed in 1.3.1

How to fix

Upgrade to a fixed version: Chromium libwebp 1.3.1. Check the vendor advisory for mitigations.

References

https://chromium.googlesource.com/webm/libwebp
https://security.gentoo.org/glsa/202309-05
https://chromium.googlesource.com/webm/libwebp
https://security.gentoo.org/glsa/202309-05

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