LiveActive security incident?Get immediate response
CVE Record

CVE-2025-38154: bpf, sockmap: Avoid using sk_socket after free when sending

In the Linux kernel, the following vulnerability has been resolved: bpf, sockmap: Avoid using sk_socket after free when sending The sk->sk_socket is not locked or referenced in backlog thread, and during the call to skb_send_sock(), there is a race condition with the release of sk_socket. All types of sockets(tcp/udp/unix/vsock) will be affected. Race conditions: ''' CPU0 CPU1 backlog::skb_send_sock sendmsg_unlocked sock_sendmsg sock_sendmsg_nosec close(fd): ... ops->release() -> sock_map_close() sk_socket->ops = NULL free(socket) sock->ops->sendmsg ^ panic here ''' The ref of psock become 0 after sock_map_close() executed. ''' void sock_map_close() { ... if (likely(psock)) { ... // !! here we remove psock and the ref of psock become 0 sock_map_remove_links(sk, psock) psock = sk_psock_get(sk); if (unlikely(!psock)) goto no_psock; <=== Control jumps here via goto ... cancel_delayed_work_sync(&psock->work); <=== not executed sk_psock_put(sk, psock); ... } ''' Based on the fact that we already wait for the workqueue to finish in sock_map_close() if psock is held, we simply increase the psock reference count to avoid race conditions. With this patch, if the backlog thread is running, sock_map_close() will wait for the backlog thread to complete and cancel all pending work. If no backlog running, any pending work that hasn't started by then will fail when invoked by sk_psock_get(), as the psock reference count have been zeroed, and sk_psock_drop() will cancel all jobs via cancel_delayed_work_sync(). In summary, we require synchronization to coordinate the backlog thread and close() thread. The panic I catched: ''' Workqueue: events sk_psock_backlog RIP: 0010:sock_sendmsg+0x21d/0x440 RAX: 0000000000000000 RBX: ffffc9000521fad8 RCX: 0000000000000001 ... Call Trace: <TASK> ? die_addr+0x40/0xa0 ? exc_general_protection+0x14c/0x230 ? asm_exc_general_protection+0x26/0x30 ? sock_sendmsg+0x21d/0x440 ? sock_sendmsg+0x3e0/0x440 ? __pfx_sock_sendmsg+0x10/0x10 __skb_send_sock+0x543/0xb70 sk_psock_backlog+0x247/0xb80 ... '''

HighCVSS 7.8Not KEV-listedUpdated
Discuss exposureBack to CVEs
Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

A timing flaw in Linux BPF sockmap handling can use a socket after it has been closed and freed. A low-privileged local user or workload may be able to trigger serious kernel failure; the report demonstrates a panic. The supplied evidence does not establish a practical path to data theft, modification, or privilege escalation.

Executive priority

Treat this as expedited kernel maintenance, especially on multi-tenant systems or hosts exposing BPF facilities to untrusted workloads. Accelerate remediation where kernel crashes have appeared. The sources do not support declaring an active-exploitation emergency, but the local low-privilege vector and potential system-wide impact justify high priority.

Technical view

The sockmap backlog worker calls skb_send_sock() without holding a reference to sk_socket, allowing close() to free the socket before sendmsg dereferences its operations table. The stable fix retains the psock reference so sock_map_close() synchronizes with active backlog work and cancels pending work safely.

Likely exposure

Likely exposure is Linux hosts where a low-privileged local user or workload can exercise BPF sockmap send paths. The bundle says TCP, UDP, Unix, and vsock sockets are affected. Its mixed commit and release data, including an ambiguous "0" entry, is insufficient for reliable distribution-package mapping; verify each vendor kernel.

Exploitation context

The record is not in KEV, and the supplied sources do not report active exploitation or a public proof of concept. CVSS describes a local, low-complexity attack requiring low privileges and no user interaction. Evidence in the bundle demonstrates a kernel panic, not a practical privilege-escalation technique.

Researcher notes

This is a race-driven use-after-free involving sk_socket lifetime during asynchronous sockmap backlog sending. The bundle reports an observed panic and rates confidentiality, integrity, and availability impacts high, but it does not demonstrate those broader outcomes. Exact affected package boundaries and exploitability under distribution-specific BPF restrictions require local verification.

Mitigation direction

  • Inventory running kernels and map distribution packages to vendor advisories or the cited stable fixes.
  • Install the vendor-supplied kernel containing the backported fix, then reboot into it.
  • Until patched, reduce untrusted local access and unnecessary BPF sockmap use after compatibility review.
  • Confirm backport status with the distributor rather than relying only on upstream version numbers.

Validation and detection

  • Confirm the running kernel after reboot matches the patched vendor package.
  • Verify applicable source contains the psock reference-count synchronization from the cited stable commits.
  • Review kernel logs for sock_sendmsg faults, sk_psock_backlog crashes, or general-protection faults.
  • Test legitimate TCP, UDP, Unix, and vsock sockmap workloads for stability after remediation.
Prepared
Confidence
medium
Sources
9

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cve · low confidence lookup

CVE-2025-38154 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

Open ATT&CK lookup
Vulnerability profileCVE Program record
Severity
High
CVSS
7.8 (3.1)
Known Exploited
No
Published

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

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

1CVSS vectors
3Timeline events
1ADP providers
8Source links

CVSS vector scores

1 official score

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
7.8CVSS 3.1HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H1.85.9Linux

Vulnerability scoring details

Base CVSS 3.1 score

7.8High
CVSS 3.1 vector shape for CVE-2025-38154Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

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

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CVECVE Program Container

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux4959ffc65a0e94f8acaac20deac49f89e6ded52d, 5eabdf17fed2ad41b836bb4055ec36d95e512c50, e946428439a0d2079959f5603256ac51b6047017, 4b4647add7d3c8530493f7247d11e257ee425bf0, 4b4647add7d3c8530493f7247d11e257ee425bf0, 4b4647add7d3c8530493f7247d11e257ee425bf0, 3627605de498639a3c586c8684d12c89cba11073, 5.15.162, 6.1.95, 6.6.35, 6.9.6unaffected
LinuxLinux6.10, 0, 5.15.186, 6.1.142, 6.6.94, 6.12.34, 6.15.3, 6.16affected
Weakness

CWE details

No CWE listed

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.