Vulnerability-Lookup

OPENSUSE-SU-2026:21501-1

Vulnerability from csaf_opensuse - Published: 2026-07-29 09:24 - Updated: 2026-09-17 17:40

Summary

Security update for s2n

Severity

Moderate

Notes

Title of the patch: Security update for s2n

Description of the patch: This update for s2n fixes the following issues: Changes in s2n: - CVE-2026-16318: Denial of Service due to memory leak in QUIC transport parameters handler (bsc#1272352) - CVE-2026-16317: man-in-the-middle attack can silently discard individual application data records

Patchnames: openSUSE-Leap-16.0-packagehub-452

CVE-2026-16317

6.5 (Medium)


                
                  CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:L

Affected products

Recommended 8 products

Product	Version	Remediation
Unresolved product id: openSUSE Leap 16.0:libs2n0unstable-0:1.5.1-bp160.2.1.aarch64	—	Vendor Fix
Unresolved product id: openSUSE Leap 16.0:libs2n0unstable-0:1.5.1-bp160.2.1.ppc64le	—	Vendor Fix
Unresolved product id: openSUSE Leap 16.0:libs2n0unstable-0:1.5.1-bp160.2.1.s390x	—	Vendor Fix
Unresolved product id: openSUSE Leap 16.0:libs2n0unstable-0:1.5.1-bp160.2.1.x86_64	—	Vendor Fix
Unresolved product id: openSUSE Leap 16.0:s2n-devel-0:1.5.1-bp160.2.1.aarch64	—	Vendor Fix
Unresolved product id: openSUSE Leap 16.0:s2n-devel-0:1.5.1-bp160.2.1.ppc64le	—	Vendor Fix
Unresolved product id: openSUSE Leap 16.0:s2n-devel-0:1.5.1-bp160.2.1.s390x	—	Vendor Fix
Unresolved product id: openSUSE Leap 16.0:s2n-devel-0:1.5.1-bp160.2.1.x86_64	—	Vendor Fix

Threats

Impact moderate

CVE-2026-16318

5.3 (Medium)


                
                  CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Affected products

Recommended 8 products, the same list as for CVE-2026-16317

Threats

Impact moderate

References

9 references

URL	Category
https://www.suse.com/support/security/rating/	external
https://ftp.suse.com/pub/projects/security/csaf/o…	self
https://bugzilla.suse.com/1272352	self
https://www.suse.com/security/cve/CVE-2026-16317/	self
https://www.suse.com/security/cve/CVE-2026-16318/	self
https://www.suse.com/security/cve/CVE-2026-16317	external
https://bugzilla.suse.com/1272354	external
https://www.suse.com/security/cve/CVE-2026-16318	external
https://bugzilla.suse.com/1272349	external

JSON

To clipboard

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          "text": "Missing validation of the outer content_type byte on TLS 1.3 encrypted records in s2n-tls allows an active man-in-the-middle to silently discard individual application data records without either endpoint detecting the modification. RFC 8446 Section 5.2 requires that the outer content_type of all encrypted TLS 1.3 records must be application_data (0x17). The s2n-tls AEAD implementation hardcodes this value in the additional authenticated data rather than using the actual wire byte, so the outer content_type is not covered by the authentication tag. \n\n\n\nThis enables selective suppression of application data. In HTTP pipelining scenarios, dropping a TLS record containing an HTTP request can cause request/response desynchronization, where subsequent responses are delivered to the wrong requests. In write-heavy workloads, a dropped record containing a write request can result in undetectable data loss when the client interprets a subsequent success response as confirmation of the dropped write.\n\n\n\nAll TLS 1.3 connections are affected. Both TLS clients and servers are affected. TLS 1.2 and QUIC connections are not affected.\n\n\n\nWe recommend you upgrade s2n-tls to version v1.7.6",
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          "text": "The QUIC transport parameters extension handler in s2n-tls incorrectly uses s2n_alloc instead of s2n_realloc to store the peer\u0027s transport parameters. When a TLS 1.3 connection goes through a HelloRetryRequest, the handler is called twice on the same connection. On the second call, s2n_alloc zeroes the existing pointer before allocating new memory, causing the first allocation to be leaked.\n\n\n\nThis can occur during normal QUIC traffic when a client offers a key share group the server does not prefer. An unauthenticated user can amplify the issue by deliberately forcing HelloRetryRequests, causing up to approximately 64 KB of unreachable memory per handshake. Over time, this can lead to increased memory consumption on long-running server processes. The unreachable memory is only reclaimed when the process is restarted.\n\n\n\nOnly server-side QUIC-enabled deployments are affected. Non-QUIC TLS connections are not affected.\n\n\n\nWe recommend you upgrade s2n-tls to version v1.7.6",
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}

CVE-2026-16317 (GCVE-0-2026-16317)

Vulnerability from cvelistv5 – Published: 2026-07-21 20:12 – Updated: 2026-07-22 19:41

Title

Silent Drop of TLS 1.3 Encrypted Records in s2n-tls

Summary

Missing validation of the outer content_type byte on TLS 1.3 encrypted records in s2n-tls allows an active man-in-the-middle to silently discard individual application data records without either endpoint detecting the modification. RFC 8446 Section 5.2 requires that the outer content_type of all encrypted TLS 1.3 records must be application_data (0x17). The s2n-tls AEAD implementation hardcodes this value in the additional authenticated data rather than using the actual wire byte, so the outer content_type is not covered by the authentication tag. This enables selective suppression of application data. In HTTP pipelining scenarios, dropping a TLS record containing an HTTP request can cause request/response desynchronization, where subsequent responses are delivered to the wrong requests. In write-heavy workloads, a dropped record containing a write request can result in undetectable data loss when the client interprets a subsequent success response as confirmation of the dropped write. All TLS 1.3 connections are affected. Both TLS clients and servers are affected. TLS 1.2 and QUIC connections are not affected. We recommend you upgrade s2n-tls to version v1.7.6

Severity

6.5 (Medium)


                        
                          CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:L

8.3 (High)


                        
                          CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:L/SC:N/SI:L/SA:N

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-07-22 19:31 UTC

CWE

CWE-354 - Improper validation of integrity check value

Assigner

AMZN mitre root

References

3 references

URL	Tags
https://github.com/aws/s2n-tls/releases/tag/v1.7.6	release-notespatch
https://aws.amazon.com/security/security-bulletin…	vendor-advisory
https://github.com/aws/s2n-tls/security/advisorie…	release-notes

Impacted products

1 product

Vendor	Product	Version
AWS	s2n-tls	Affected: 0 , ≤ 1.7.5 (custom) cpe:2.3:a:aws:s2n-tls::::::::

Show details on NVD website

JSON

To clipboard

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CVE-2026-16318 (GCVE-0-2026-16318)

Vulnerability from cvelistv5 – Published: 2026-07-21 20:14 – Updated: 2026-07-22 19:41

Title

QUIC Transport Parameters Memory Leak During HelloRetryRequest in s2n-tls

Summary

The QUIC transport parameters extension handler in s2n-tls incorrectly uses s2n_alloc instead of s2n_realloc to store the peer's transport parameters. When a TLS 1.3 connection goes through a HelloRetryRequest, the handler is called twice on the same connection. On the second call, s2n_alloc zeroes the existing pointer before allocating new memory, causing the first allocation to be leaked. This can occur during normal QUIC traffic when a client offers a key share group the server does not prefer. An unauthenticated user can amplify the issue by deliberately forcing HelloRetryRequests, causing up to approximately 64 KB of unreachable memory per handshake. Over time, this can lead to increased memory consumption on long-running server processes. The unreachable memory is only reclaimed when the process is restarted. Only server-side QUIC-enabled deployments are affected. Non-QUIC TLS connections are not affected. We recommend you upgrade s2n-tls to version v1.7.6

Severity

5.3 (Medium)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

6.9 (Medium)


                        
                          CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N

SSVC

Exploitation: none Automatable: yes Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-07-22 19:34 UTC

CWE

CWE-401 - Missing release of memory after effective lifetime

Assigner

AMZN mitre root

References

3 references

URL	Tags
https://github.com/aws/s2n-tls/releases/tag/v1.7.6	release-notespatch
https://staging.prod.website.marketing.aws.dev/se…	vendor-advisory
https://github.com/aws/s2n-tls/security/advisorie…	release-notes

Impacted products

1 product

Vendor	Product	Version
Amazon	s2n-tls	Affected: 0 , ≤ v1.7.5 (custom) cpe:2.3:a:amazon:s2n-tls::::::::

Show details on NVD website

JSON

To clipboard

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Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.

Action not permitted

OPENSUSE-SU-2026:21501-1

CVE-2026-16317 (GCVE-0-2026-16317)

CVE-2026-16318 (GCVE-0-2026-16318)

Tags

Sightings

Nomenclature

Related by attack behaviour