Description
Issue summary: The OpenSSL QUIC server, when configured to not preform address
validation, can be forced to count incoming packets multiple times in its
unvalidated credit computation, leading to a violation of the RFC 9000
unvalidated connection amplification limit of 3 times the amount of data
received.
Impact summary: A remote attacker able to spoof packets to a server using the
OpenSSL QUIC implementation might use the server for an amplification of
a DDoS attack.
CWE: CWE-440: Expected Behavior Violation
Description: OpenSSL's QUIC stack, when operating as a server, enforces client
address validation (RFC 9000, Section 8), to confirm the peer address is not
used for a traffic amplification attack. If this feature is disabled on the
server, the QUIC stack limits the amount of server data that can be sent to 3
times the amount of data received from the peer address, until such time as the
TLS handshake is completed.
The OpenSSL QUIC server, when operating in non-validation mode, adds the
length of the whole datagram received to the unvalidated credit limit when
processing each QUIC packet in the datagram. A remote peer may,
after establishing a connection with an initial client hello frame, send a
subsequent datagram containing multiple QUIC packets, leading the server to
account the entire datagram length for each packet in the datagram, resulting
in the server believing that the peer has sent more data than it actually has,
thereby violating the 3x amplification limit mandated by the RFC.
FIPS impact: no
As the QUIC stack lives outside the FIPS module boundary, no FIPS modules
are affected by this CVE.
validation, can be forced to count incoming packets multiple times in its
unvalidated credit computation, leading to a violation of the RFC 9000
unvalidated connection amplification limit of 3 times the amount of data
received.
Impact summary: A remote attacker able to spoof packets to a server using the
OpenSSL QUIC implementation might use the server for an amplification of
a DDoS attack.
CWE: CWE-440: Expected Behavior Violation
Description: OpenSSL's QUIC stack, when operating as a server, enforces client
address validation (RFC 9000, Section 8), to confirm the peer address is not
used for a traffic amplification attack. If this feature is disabled on the
server, the QUIC stack limits the amount of server data that can be sent to 3
times the amount of data received from the peer address, until such time as the
TLS handshake is completed.
The OpenSSL QUIC server, when operating in non-validation mode, adds the
length of the whole datagram received to the unvalidated credit limit when
processing each QUIC packet in the datagram. A remote peer may,
after establishing a connection with an initial client hello frame, send a
subsequent datagram containing multiple QUIC packets, leading the server to
account the entire datagram length for each packet in the datagram, resulting
in the server believing that the peer has sent more data than it actually has,
thereby violating the 3x amplification limit mandated by the RFC.
FIPS impact: no
As the QUIC stack lives outside the FIPS module boundary, no FIPS modules
are affected by this CVE.
Published:
2026-09-29
Score:
n/a
EPSS:
n/a
KEV:
No
Impact:
n/a
Action:
n/a
Analysis
No analysis available yet.
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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No data available yet.
Remediation
No remediation available yet.
Tracking
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Advisories
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References
History
Tue, 29 Sep 2026 15:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | Issue summary: The OpenSSL QUIC server, when configured to not preform address validation, can be forced to count incoming packets multiple times in its unvalidated credit computation, leading to a violation of the RFC 9000 unvalidated connection amplification limit of 3 times the amount of data received. Impact summary: A remote attacker able to spoof packets to a server using the OpenSSL QUIC implementation might use the server for an amplification of a DDoS attack. CWE: CWE-440: Expected Behavior Violation Description: OpenSSL's QUIC stack, when operating as a server, enforces client address validation (RFC 9000, Section 8), to confirm the peer address is not used for a traffic amplification attack. If this feature is disabled on the server, the QUIC stack limits the amount of server data that can be sent to 3 times the amount of data received from the peer address, until such time as the TLS handshake is completed. The OpenSSL QUIC server, when operating in non-validation mode, adds the length of the whole datagram received to the unvalidated credit limit when processing each QUIC packet in the datagram. A remote peer may, after establishing a connection with an initial client hello frame, send a subsequent datagram containing multiple QUIC packets, leading the server to account the entire datagram length for each packet in the datagram, resulting in the server believing that the peer has sent more data than it actually has, thereby violating the 3x amplification limit mandated by the RFC. FIPS impact: no As the QUIC stack lives outside the FIPS module boundary, no FIPS modules are affected by this CVE. | |
| Title | QUIC Unvalidated Amplification Credit may be Over Accounted | |
| Weaknesses | CWE-440 | |
| References |
|
|
Subscriptions
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MITRE
Status: PUBLISHED
Assigner: openssl
Published:
Updated: 2026-09-29T15:32:12.944Z
Reserved: 2026-04-01T17:36:26.324Z
Link: CVE-2026-35191
Vulnrichment
No data.
NVD
No data.
Redhat
No data.
OpenCVE Enrichment
No data.
Weaknesses
-
CWE-440
Expected Behavior Violation