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NVD / CVE Program· CNA Linux

CVE-2025-21683: bpf: Fix bpf_sk_select_reuseport() memory leak

Noroxi assessment

Priority: Monitor (action score 22/100)

  • 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: 0.22% (FIRST EPSS).
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Linux Linux 0ab52a8ca6e156a64c51b5e7456cac9a0ebfd9bf, b02e70be498b138e9c21701c2f33f4018ca7cd5e, b3af60928ab9129befa65e6df0310d27300942bf; azl3 kernel 6.6.64.2-9 on Azure Linux 3.0 6.6.76.1-1; azl3 kernel 6.6.76.1-1 on Azure Linux 3.0 6.6.76.1-1.

Low priority for now. Upgrade to Linux Linux 0ab52a8ca6e156a64c51b5e7456cac9a0ebfd9bf, b02e70be498b138e9c21701c2f33f4018ca7cd5e, b3af60928ab9129befa65e6df0310d27300942bf; azl3 kernel 6.6.64.2-9 on Azure Linux 3.0 6.6.76.1-1; azl3 kernel 6.6.76.1-1 on Azure Linux 3.0 6.6.76.1-1 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

In the Linux kernel, the following vulnerability has been resolved: bpf: Fix bpf_sk_select_reuseport() memory leak As pointed out in the original comment, lookup in sockmap can return a TCP ESTABLISHED socket. Such TCP socket may have had SO_ATTACH_REUSEPORT_EBPF set before it was ESTABLISHED. In other words, a non-NULL sk_reuseport_cb does not imply a non-refcounted socket. Drop sk's reference in both error paths. unreferenced object 0xffff888101911800 (size 2048): comm "test_progs", pid 44109, jiffies 4297131437 hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 80 00 01 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace (crc 9336483b): __kmalloc_noprof+0x3bf/0x560 __reuseport_alloc+0x1d/0x40 reuseport_alloc+0xca/0x150 reuseport_attach_prog+0x87/0x140 sk_reuseport_attach_bpf+0xc8/0x100 sk_setsockopt+0x1181/0x1990 do_sock_setsockopt+0x12b/0x160 __sys_setsockopt+0x7b/0xc0 __x64_sys_setsockopt+0x1b/0x30 do_syscall_64+0x93/0x180 entry_SYSCALL_64_after_hwframe+0x76/0x7e

MediumCVSS 5.5 · v3.1—No exploit Fix available
Published
Jan 31, 2025
Updated
Oct 15, 2026
EPSS
0.2% · 13th percentile

Report tools

JSON

Action score

22

Monitor

Low priority for now.

CVSS
22 / 40 · 5.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

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.

Follow CVE-2025-21683

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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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.

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Affected 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.

VendorProduct
linuxlinux kernel

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • linux linux kernel5.8 and later · before 5.15.177
  • linux linux kernel5.16 and later · before 6.1.127
  • linux linux kernel6.2 and later · before 6.6.74
  • linux linux kernel6.7 and later · before 6.12.11
  • linux linux kernel6.13

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 5.8affected
    • 64d85290d79c0677edb5a8ee2295b36c022fa5df and later · before bb36838dac7bb334a3f3d7eb29875593ec9473fcaffected · git
    • 64d85290d79c0677edb5a8ee2295b36c022fa5df and later · before 0ab52a8ca6e156a64c51b5e7456cac9a0ebfd9bfaffected · git
    • 64d85290d79c0677edb5a8ee2295b36c022fa5df and later · before d0a3b3d1176d39218b8edb2a2d03164942ab9ccdaffected · git
    • 64d85290d79c0677edb5a8ee2295b36c022fa5df and later · before b02e70be498b138e9c21701c2f33f4018ca7cd5eaffected · git
    • 64d85290d79c0677edb5a8ee2295b36c022fa5df and later · before cccd51dd22574216e64e5d205489e634f86999f3affected · git
    • 64d85290d79c0677edb5a8ee2295b36c022fa5df and later · before b3af60928ab9129befa65e6df0310d27300942bfaffected · git
    • before 5.8not affected · semver
    • 5.10.234 and later · up to and including 5.10.*not affected · semver
    • 5.15.177 and later · up to and including 5.15.*not affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.128-16.1.128-1
Debian:13linuxbefore 6.12.11-16.12.11-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-31431crypto: algif_aead - Revert to operating out-of-placeKEV
    90Now
  • CVE-2022-0847A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copy_page_to_iter_pipe KEV
    89Now
  • CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV
    85Now

Published before and after this one in the same product

  • ← EarlierCVE-2025-21680Jan 31, 2025 · pktgen: Avoid out-of-bounds access in get_imix_entries
    31Monitor
  • ← EarlierCVE-2025-21681Jan 31, 2025 · openvswitch: fix lockup on tx to unregistering netdev with carrier
    22Monitor
  • Later →CVE-2024-57948Jan 31, 2025 · mac802154: check local interfaces before deleting sdata list
    22Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux0ab52a8ca6e156a64c51b5e7456cac9a0ebfd9bfVendor (CNA)
Linux Linuxb02e70be498b138e9c21701c2f33f4018ca7cd5eVendor (CNA)
Linux Linuxb3af60928ab9129befa65e6df0310d27300942bfVendor (CNA)
Linux Linuxbb36838dac7bb334a3f3d7eb29875593ec9473fcVendor (CNA)
Linux Linuxcccd51dd22574216e64e5d205489e634f86999f3Vendor (CNA)
Linux Linuxd0a3b3d1176d39218b8edb2a2d03164942ab9ccdVendor (CNA)
azl3 kernel 6.6.64.2-9 on Azure Linux 3.06.6.76.1-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
azl3 kernel 6.6.76.1-1 on Azure Linux 3.06.6.76.1-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
cbl2 kernel 5.15.176.3-3 on CBL Mariner 2.05.15.180.1-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
cbl2 kernel 5.15.176.3-3 on CBL-Mariner 2.05.15.180.1-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
cbl2 kernel 5.15.180.1-1 on CBL Mariner 2.05.15.180.1-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
debian:linux6.1.128-1 · Debian:12Package 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.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

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).

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-401 · Missing Release of Memory after Effective Lifetime

CVSS vector

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

nvd-primary

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

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (8 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records