QUIC Unvalidated Amplification Credit may be Over Accounted
Noroxi assessment
Priority: Monitor (action score 14/100)
- The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
- Probability of exploitation in the next 30 days: 0.35% (FIRST EPSS).
- Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. Special conditions such as timing or configuration are required.
- Fixed version: OpenSSL OpenSSL 3.5.9, 3.6.5, 4.0.3; azl3 cloud-hypervisor 52.0.152-1 on Azure Linux 3.0 Release Notes; azl3 kata-containers 4.1.0.kata0-1 on Azure Linux 3.0 Release Notes.
- Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).
Low priority for now. Upgrade to OpenSSL OpenSSL 3.5.9, 3.6.5, 4.0.3; azl3 cloud-hypervisor 52.0.152-1 on Azure Linux 3.0 Release Notes; azl3 kata-containers 4.1.0.kata0-1 on Azure Linux 3.0 Release Notes or later.
Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it
Primary sources: NVD · CVE.org · FIRST EPSS
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.
- Published
- Sep 29, 2026
- Updated
- Oct 8, 2026
- EPSS
- 0.3% · 28th percentile
- CWE
- CWE-440
Report tools
Action score
14
Monitor
Low priority for now.
- CVSS
- 14 / 40 · 3.7 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.3%
CISA SSVC decision
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
Vulnrichment: CISA's decision-tree inputs.
Get told when this record changes
- Not in KEV: no record of exploitation in the wild
- No public exploit code on record
- A fix has been released
If any of these changes, we'll tell you in the daily email digest.
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Noroxi analysis
What does it mean in your environment?
The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.
We use this product, ask for helpAffected systems
Is your version affected?
Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.
| Vendor | Product | CPE |
|---|---|---|
| openssl | openssl | cpe:2.3:a:openssl:openssl |
Check your server's TLS configuration
The OpenSSL version can't be seen from outside; the free SSL checker tests your certificate, enabled TLS versions and weak ciphers. Confirm the version on your server with the package manager.
Run the SSL checkAffected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- openssl openssl3.5.0 and later · before 3.5.9
- openssl openssl3.6.0 and later · before 3.6.5
- openssl openssl4.0.0 and later · before 4.0.3
Versions reported by the vendor
Affected version ranges reported by the assigning authority (openssl). Independent of NVD's CPE analysis and usually ahead of it.
OpenSSL OpenSSL
- 4.0.0 and later · before 4.0.3affected · semver
- 3.6.0 and later · before 3.6.5affected · semver
- 3.5.0 and later · before 3.5.9affected · semver
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Debian:13 | openssl | before 3.5.7-1~deb13u3 | 3.5.7-1~deb13u3 |
| Debian:14 | openssl | before 3.6.5-1 | 3.6.5-1 |
| openSUSE:Leap 16.0 | openssl-3 | before 3.5.0-160000.11.1 | 3.5.0-160000.11.1 |
| Red Hat:hummingbird:1 | openssl | before 0:3.5.9-0.1.hum1 | 0:3.5.9-0.1.hum1 |
| Red Hat:hummingbird:1 | openssl-config-fips | before 0:3.5.9-0.1.hum1 | 0:3.5.9-0.1.hum1 |
| Red Hat:hummingbird:1 | openssl-devel | before 0:3.5.9-0.1.hum1 | 0:3.5.9-0.1.hum1 |
| Red Hat:hummingbird:1 | openssl-devel-engine | before 0:3.5.9-0.1.hum1 | 0:3.5.9-0.1.hum1 |
| Red Hat:hummingbird:1 | openssl-fips-provider-upstream | before 0:3.5.9-0.1.hum1 | 0:3.5.9-0.1.hum1 |
| Red Hat:hummingbird:1 | openssl-libs | before 0:3.5.9-0.1.hum1 | 0:3.5.9-0.1.hum1 |
| Red Hat:hummingbird:1 | openssl-perl | before 0:3.5.9-0.1.hum1 | 0:3.5.9-0.1.hum1 |
| Red Hat:hummingbird:1 | openssl3 | before 0:3.5.9-0.1.hum1 | 0:3.5.9-0.1.hum1 |
| Red Hat:hummingbird:1 | openssl3-devel | before 0:3.5.9-0.1.hum1 | 0:3.5.9-0.1.hum1 |
| Red Hat:hummingbird:1 | openssl3-devel-engine | before 0:3.5.9-0.1.hum1 | 0:3.5.9-0.1.hum1 |
| Red Hat:hummingbird:1 | openssl3-libs | before 0:3.5.9-0.1.hum1 | 0:3.5.9-0.1.hum1 |
| SUSE:Linux Enterprise Module for Basesystem 15 SP7 | openssl-3 | before 3.5.0-150700.5.53.2 | 3.5.0-150700.5.53.2 |
| SUSE:Linux Micro 6.2 | openssl-3 | before 3.5.0-160000.11.1 | 3.5.0-160000.11.1 |
Same product
openssl: all recordsOther highest-scoring records for the same primary product.
- CVE-2014-0160The (1) TLS and (2) DTLS implementations in OpenSSL 1.0.1 before 1.0.1g do not properly handle Heartbeat Extension packets, which allows remKEV90Now
- CVE-2021-3711SM2 Decryption Buffer Overflow65This week
- CVE-2003-0545Double free vulnerability in OpenSSL 0.9.7 allows remote attackers to cause a denial of service (crash) and possibly execute arbitrary code 65This week
Published before and after this one in the same product
- ← EarlierCVE-2026-75803Aug 25, 2026 · AEAD Forgeries with Empty Ciphertext When Using EVP_Cipher()36Monitor
- ← EarlierCVE-2026-35189Sep 29, 2026 · Excessive Memory Allocation in Relative CRLDP Processing21Monitor
- Later →CVE-2026-42772Sep 29, 2026 · Potential CPU DoS via O(n^2) Fragment Reassembly in QUIC21Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| OpenSSL OpenSSL | 3.5.9 | Vendor (CNA) |
| OpenSSL OpenSSL | 3.6.5 | Vendor (CNA) |
| OpenSSL OpenSSL | 4.0.3 | Vendor (CNA) |
| azl3 cloud-hypervisor 52.0.152-1 on Azure Linux 3.0 | Release Notes | Microsoft (MSRC) |
| azl3 kata-containers 4.1.0.kata0-1 on Azure Linux 3.0 | Release Notes | Microsoft (MSRC) |
| azl3 openvmm 0.1.0-1 on Azure Linux 3.0 | Release Notes | Microsoft (MSRC) |
| azl3 rust 1.75.0-31 on Azure Linux 3.0 | Release Notes | Microsoft (MSRC) |
| azl3 rust 1.96.1-2 on Azure Linux 3.0 | Release Notes | Microsoft (MSRC) |
| debian:openssl | 3.5.7-1~deb13u3 · Debian:13 | Package registry (OSV) |
| opensuse:openssl-3 | 3.5.0-160000.11.1 · openSUSE:Leap 16.0 | Package registry (OSV) |
| red hat:openssl | 0:3.5.9-0.1.hum1 · Red Hat:hummingbird:1 | Package registry (OSV) |
| red hat:openssl-config-fips | 0:3.5.9-0.1.hum1 · Red Hat:hummingbird:1 | Package registry (OSV) |
| red hat:openssl-devel | 0:3.5.9-0.1.hum1 · Red Hat:hummingbird:1 | Package registry (OSV) |
| red hat:openssl-devel-engine | 0:3.5.9-0.1.hum1 · Red Hat:hummingbird:1 | Package registry (OSV) |
| red hat:openssl-fips-provider-upstream | 0:3.5.9-0.1.hum1 · Red Hat:hummingbird:1 | Package registry (OSV) |
| red hat:openssl-libs | 0:3.5.9-0.1.hum1 · Red Hat:hummingbird:1 | Package registry (OSV) |
| red hat:openssl-perl | 0:3.5.9-0.1.hum1 · Red Hat:hummingbird:1 | Package registry (OSV) |
| red hat:openssl3 | 0:3.5.9-0.1.hum1 · Red Hat:hummingbird:1 | Package registry (OSV) |
| red hat:openssl3-devel | 0:3.5.9-0.1.hum1 · Red Hat:hummingbird:1 | Package registry (OSV) |
| red hat:openssl3-devel-engine | 0:3.5.9-0.1.hum1 · Red Hat:hummingbird:1 | Package registry (OSV) |
| red hat:openssl3-libs | 0:3.5.9-0.1.hum1 · Red Hat:hummingbird:1 | Package registry (OSV) |
| suse:openssl-3 | 3.5.0-150700.5.53.2 · SUSE:Linux Enterprise Module for Basesystem 15 SP7 | Package registry (OSV) |
| suse:openssl-3 | 3.5.0-160000.11.1 · SUSE:Linux Micro 6.2 | Package registry (OSV) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
- Published
- Fix recordedsame day
- TodayOct 25, 2026+26 d
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
- Ali Firasreporter
- Nikolas Gauder (NVIDIA)reporter
- Neil Hormanremediation developer
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
National notice (Türkiye Cybersecurity Directorate / USOM)
Official security notices citing this record; remediation advice is on the agency's page.
- TR-26-1218 · Sep 30, 2026(OpenSSL Güvenlik Zafiyeti)
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- No account or password is required.
- No user action is required.
- Special conditions such as timing or configuration are required.
If successful
- Confidentiality
- none
- Integrity
- none
- Availability
- low · the service can be disrupted
- Attack vector
- Network
- Attack complexity
- High
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- None
- Integrity impact
- None
- Availability impact
- Low
Weakness class (CWE)
CWE-440 · Expected Behavior ViolationCVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L
nvd-secondary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
MITRE has no CAPEC/ATT&CK mapping for this CWE.
Change log
- CVSS— → 3.7
- Severity— → low
- SSVC exploitation— → none
- Exploit maturity— → none
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
Show all references (3 more)Show less
Vendor advisories and official records. Exploit/PoC links are deliberately left out.