CVE-2025-39812

Availability loss via uninitialized SCTP IPv6 fields

Published Sep 16, 2025 · Updated Sep 16, 2025

Improper initialization in affected Linux kernel releases allows local users to interrupt availability through SCTP listen operations. sctp_v6_from_sk leaves sin6_scope_id and sin6_flowinfo uncleared, and bind-conflict comparison subsequently reads the uninitialized scope identifier. Reaching the flaw requires local access and an SCTP IPv6 listen operation; the Linux account documents undefined behavior rather than a specific crash mode.

CVSS severity5.5
Medium
EPSS probability0.17%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper initialization in affected Linux kernel releases allows local users to interrupt availability through SCTP listen operations. sctp_v6_from_sk leaves sin6_scope_id and sin6_flowinfo uncleared, and bind-conflict comparison subsequently reads the uninitialized scope identifier. Reaching the flaw requires local access and an SCTP IPv6 listen operation; the Linux account documents undefined behavior rather than a specific crash mode.

The record

CVE
CVE-2025-39812
Published
Sep 16, 2025
Updated
Sep 16, 2025
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 16, 2025CVE publishedPublication date reported by the CVE source.
  2. Sep 16, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <17d6c7747045e9b802c2f5dfaba260d309d831ae
  2. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <1bbc0c02aea1f1c405bd1271466889c25a1fe01b
  3. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <2e8750469242cad8f01f320131fd5a6f540dbb99
  4. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <45e4b36593edffb7bbee5828ae820bc10a9fa0f3
  5. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <463aa96fca6209bb205f49f7deea3817d7ddaa3a
  6. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <65b4693d8bab5370cfcb44a275b4d8dcb06e56bf
  7. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <9546934c2054bba1bd605c44e936619159a34027
  8. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <f6c2cc99fc2387ba6499facd6108f6543382792d
  9. Affected versionversion=2.6.12

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <17d6c7747045e9b802c2f5dfaba260d309d831ae; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <1bbc0c02aea1f1c405bd1271466889c25a1fe01b; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <2e8750469242cad8f01f320131fd5a6f540dbb99; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <45e4b36593edffb7bbee5828ae820bc10a9fa0f3; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <463aa96fca6209bb205f49f7deea3817d7ddaa3a; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <65b4693d8bab5370cfcb44a275b4d8dcb06e56bf; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <9546934c2054bba1bd605c44e936619159a34027; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <f6c2cc99fc2387ba6499facd6108f6543382792d; version=2.6.12

Published CVSS scores

5.3SUSECVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L
4.8SUSECVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N
5.5Amazon LinuxCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
5.5UbuntuCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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