Description
Issue summary: The AES-GCM-SIV implementation treats a zero-length Additional
Authenticated Data (AAD) update as a reset of all the AAD supplied so far,
instead of leaving the AAD unchanged. An application that supplies its AAD in
several fragments, one of which is empty, therefore produces or verifies
messages whose authentication tag does not cover the AAD supplied before
the empty fragment.
Impact summary: Data an application intended to authenticate alongside a
message is silently left unauthenticated. An attacker can forge the AAD of such
a message.
CWE: CWE-325: Missing Cryptographic Step
Description: An application passing AAD in multiple chunks of which some have
zero length will have the previous AAD chunks effectively unauthenticated. Also,
on context re-initialisation, the AAD was not reset, which meant that any AAD
accumulated from the previous context usage were also included in the AAD of the
new message.
The fix makes a zero-length AAD update a no-op and clears any accumulated AAD
whenever the context is re-initialised with a key or a nonce.
A re-initialisation that only changes parameters keeps the AAD.
FIPS impact: no
The FIPS modules are not affected, as AES-GCM-SIV is not a FIPS approved
algorithm and is implemented only in the default provider, outside the
OpenSSL FIPS module boundary.
Authenticated Data (AAD) update as a reset of all the AAD supplied so far,
instead of leaving the AAD unchanged. An application that supplies its AAD in
several fragments, one of which is empty, therefore produces or verifies
messages whose authentication tag does not cover the AAD supplied before
the empty fragment.
Impact summary: Data an application intended to authenticate alongside a
message is silently left unauthenticated. An attacker can forge the AAD of such
a message.
CWE: CWE-325: Missing Cryptographic Step
Description: An application passing AAD in multiple chunks of which some have
zero length will have the previous AAD chunks effectively unauthenticated. Also,
on context re-initialisation, the AAD was not reset, which meant that any AAD
accumulated from the previous context usage were also included in the AAD of the
new message.
The fix makes a zero-length AAD update a no-op and clears any accumulated AAD
whenever the context is re-initialised with a key or a nonce.
A re-initialisation that only changes parameters keeps the AAD.
FIPS impact: no
The FIPS modules are not affected, as AES-GCM-SIV is not a FIPS approved
algorithm and is implemented only in the default provider, outside the
OpenSSL FIPS module boundary.
Published:
2026-11-10
Score:
n/a
EPSS:
n/a
KEV:
No
Impact:
n/a
Action:
n/a
Analysis
Analysis and contextual insights are available on OpenCVE Cloud.
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| OpenSSL | OpenSSL | unaffected |
|
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Remediation
No vendor fix or workaround currently provided.
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Tracking
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Advisories
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References
History
Tue, 10 Nov 2026 18:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | Issue summary: The AES-GCM-SIV implementation treats a zero-length Additional Authenticated Data (AAD) update as a reset of all the AAD supplied so far, instead of leaving the AAD unchanged. An application that supplies its AAD in several fragments, one of which is empty, therefore produces or verifies messages whose authentication tag does not cover the AAD supplied before the empty fragment. Impact summary: Data an application intended to authenticate alongside a message is silently left unauthenticated. An attacker can forge the AAD of such a message. CWE: CWE-325: Missing Cryptographic Step Description: An application passing AAD in multiple chunks of which some have zero length will have the previous AAD chunks effectively unauthenticated. Also, on context re-initialisation, the AAD was not reset, which meant that any AAD accumulated from the previous context usage were also included in the AAD of the new message. The fix makes a zero-length AAD update a no-op and clears any accumulated AAD whenever the context is re-initialised with a key or a nonce. A re-initialisation that only changes parameters keeps the AAD. FIPS impact: no The FIPS modules are not affected, as AES-GCM-SIV is not a FIPS approved algorithm and is implemented only in the default provider, outside the OpenSSL FIPS module boundary. | |
| Title | AES-GCM-SIV AAD Forgery After Zero-length Incremental AAD Update | |
| Weaknesses | CWE-325 | |
| References |
|
|
Subscriptions
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MITRE
Status: PUBLISHED
Assigner: openssl
Published:
Updated: 2026-11-10T18:15:49.358Z
Reserved: 2026-09-10T09:08:26.966Z
Link: CVE-2026-88823
Vulnrichment
No data.
NVD
No data.
Redhat
No data.
OpenCVE Enrichment
No data.
Weaknesses