CVE-2023-1999Network attack vector

Encoder crash via stale bit-writer double free

Published Jun 20, 2023 · Updated Feb 13, 2025

Double-free in Google libwebp 0.4.2 through 1.3.0 allows attackers to trigger memory corruption via an encoder error path. EncodeAlphaInternal wipes a temporary bit writer but leaves result->bw pointing to the previous trial buffer when initialization fails. ApplyFiltersAndEncode then frees the stale pointer again; reaching the flaw requires an encoder allocation failure, and the documented outcome is a crash with memory corruption.

CVSS severity5.3
Medium
EPSS probability0.95%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Double-free in Google libwebp 0.4.2 through 1.3.0 allows attackers to trigger memory corruption via an encoder error path. EncodeAlphaInternal wipes a temporary bit writer but leaves result->bw pointing to the previous trial buffer when initialization fails. ApplyFiltersAndEncode then frees the stale pointer again; reaching the flaw requires an encoder allocation failure, and the documented outcome is a crash with memory corruption.

The record

CVE
CVE-2023-1999
Published
Jun 20, 2023
Updated
Feb 13, 2025
Vendor
Google
Product
libwebp
Classifications
CWE-415, CWE-416, T1499.004
Attack vector
network
Privileges
Unavailable

Timeline

How it unfolded

  1. Jun 20, 2023CVE publishedPublication date reported by the CVE source.
  2. Feb 13, 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=0.4.2 <1.3.0-8-ga486d800
  2. Affected versionversion=0.4.2 <1.3.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesUnavailable in this record.

What is affected?

Google · libwebpversion=0.4.2 <1.3.0-8-ga486d800; version=0.4.2 <1.3.1

Published CVSS scores

5.3Google Inc.CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N
7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-415Double Free
CWE-416Use After Free
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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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