Apache Commons Codec up to 1.22.x Blake3 doFinalize state issue

Summaryinfo

A vulnerability classified as critical has been found in Apache Commons Codec up to 1.22.x. This affects the function doFinalize of the component Blake3. This manipulation causes state issue. The identification of this vulnerability is CVE-2026-119078. It is possible to initiate the attack remotely. There is no exploit available. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability classified as critical was found in Apache Commons Codec up to 1.22.x. Affected by this vulnerability is the function doFinalize of the component Blake3. The manipulation with an unknown input leads to a state issue vulnerability. The CWE definition for the vulnerability is CWE-371. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

Apache Commons Codec's Blake3 class documented the output of its doFinalize methods as depending on any previously finalized bytes, so that consecutive calls would return different output. In fact, doFinalize does not change the hash state: calling it again without supplying more input returns the same bytes. The key-derivation example in the class Javadoc, shipped since 1.16.0, derives two keys with two consecutive doFinalize calls. Code that follows it gets identical keys, so the separation between the derived keys is lost. The same applies to any application that calls doFinalize more than once on one instance and expects new output each time. This issue affects Apache Commons Codec from 1.16.0 before 1.23.0. Version 1.23.0 corrects the documentation, but the behavior of doFinalize is unchanged. Upgrading alone does not fix affected code. Users should check their applications for repeated doFinalize calls on the same Blake3 instance and derive multiple keys by requesting the combined length in one call and splitting the output, as the updated Javadoc shows.

The advisory is shared at lists.apache.org. This vulnerability is known as CVE-2026-119078 since 10/29/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Technical details are known, but no exploit is available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 11/09/2026).

Upgrading to version 1.23.0 eliminates this vulnerability.

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Productinfo

Vendor

• Apache

Name

• Commons Codec

Version

• 1.0
• 1.1
• 1.2
• 1.3
• 1.4
• 1.5
• 1.6
• 1.7
• 1.8
• 1.9
• 1.10
• 1.11
• 1.12
• 1.13
• 1.14
• 1.15
• 1.16
• 1.17
• 1.18
• 1.19
• 1.20
• 1.21
• 1.22

License

• open-source

Website

• Vendor: https://www.apache.org/

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