Bug 2535891 - CVE-2026-75803 mesa: openssl: AEAD forgeries possible with empty ciphertext in EVP_Cipher() [fedora-all]
Summary: CVE-2026-75803 mesa: openssl: AEAD forgeries possible with empty ciphertext i...
Keywords:
Status: CLOSED NOTABUG
Alias: None
Product: Fedora
Classification: Fedora
Component: mesa
Version: rawhide
Hardware: Unspecified
OS: Unspecified
low
low
Target Milestone: ---
Assignee: Adam Jackson
QA Contact: Fedora Extras Quality Assurance
URL:
Whiteboard: {"flaws": ["c789c7ff-eb54-4cea-b506-8...
Depends On:
Blocks: CVE-2026-75803
TreeView+ depends on / blocked
 
Reported: 2026-09-17 09:06 UTC by Srikanth Balasubramanian
Modified: 2026-09-18 07:13 UTC (History)
15 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed: 2026-09-18 07:13:02 UTC
Type: ---
Embargoed:


Attachments (Terms of Use)

Description Srikanth Balasubramanian 2026-09-17 09:06:40 UTC
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.

Issue summary: ChaCha20-Poly1305 and AES-OCB decryption with an empty
ciphertext can report success without verifying the supplied authentication
tag when the operation is finalized by calling the EVP_Cipher() function.

Impact summary: Applications calling EVP_Cipher() on an empty ciphertext and
expecting the call to check the AEAD tag may accept forged messages.

CWE: CWE-354 (Improper Validation of Integrity Check Value)

Description: The EVP_Cipher() API call for AEAD ciphers behaves like a one
shot encryption and decryption call. It also verifies the AEAD tag after the
decryption operation. However for AES-OCB and ChaCha20-Poly1305 ciphers
it skipped the AEAD tag verification when an empty ciphertext was passed to
the function. The callers of this function might believe that a successful
return indicates a valid AEAD tag for these ciphers, even when that has not
truly been validated in this case.

FIPS impact: no
The FIPS modules in 4.0, 3.6, 3.5, 3.4, and 3.0 are not affected by this CVE
as the affected algorithms are not FIPS approved and thus not implemented
in the FIPS module.

Comment 1 José Expósito 2026-09-18 07:13:02 UTC
This bug report looks like a false positive. Mesa does not link to OpenSSL, as shown by these 2 commands returning empty results:

$ rpm -ql mesa mesa-* | xargs -I{} sh -c 'ldd "{}" 2>/dev/null' | grep -i 'ssl\|crypto'
$ rpm -qR mesa mesa-* 2>/dev/null | grep -i 'ssl\|crypto'

Therefore, this report is closed as not a bug.


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