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CVE-2026-98276

net: lock the socket in sock_gettstamp()

No known exploitation. EPSS puts it in the 3rd percentile. Fixed versions are out.

CVSS 3.17.8HighEPSS percentile3rd0.1% chance in 30 daysCISA KEVNot listedNo confirmed exploitation
No public exploit knownFix1 product4 fixed builds listed below

Published Updated Sources: CVE.org, NVD

NVD CVE.org

What to do

Find your product and version, then upgrade to the build on the right.

  • LinuxAffected: ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 18899e2e4023369a8f7739c2255a59a9748d8d17Upgrade to: 18899e2e4023369a8f7739c2255a59a9748d8d17Affected: ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 88c804847dd87dc613b771b392ccecdb94725032Upgrade to: 88c804847dd87dc613b771b392ccecdb94725032Affected: ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 3b12d3967e96f1b7b977d9fc352ae29a1b299a82Upgrade to: 3b12d3967e96f1b7b977d9fc352ae29a1b299a82Affected: ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 17b2a1eb97fdb2a2cbaeab3b146b26797ea9311fUpgrade to: 17b2a1eb97fdb2a2cbaeab3b146b26797ea9311f + 4 more branchesStated by: CVE record

Versions as the sources state them. Full version matrix after sign-in

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What it is

From the CVE record

In the Linux kernel, the following vulnerability has been resolved: net: lock the socket in sock_gettstamp() sk->sk_flags must only be changed while holding the socket lock, because sock_set_flag() and sock_reset_flag() use non atomic operations (__set_bit() and __clear_bit()). sock_gettstamp() is one of the last places where a bit of sk->sk_flags is changed from a syscall without owning the socket lock, through sock_enable_timestamp(sk, SOCK_TIMESTAMP). sk_set_memalloc() and sk_clear_memalloc() also change sk->sk_flags without the socket lock, but their callers (nbd, iscsi_tcp, nvme-tcp, sunrpc, wireguard) need a careful audit, this will be addressed in a separate patch. Jungwoo Lee and Wongi Lee reported an UDP socket use-after-free caused by this bug: a SIOCGSTAMPNS_NEW ioctl racing with bind() can cancel the SOCK_RCU_FREE bit that udp_lib_get_port() just set, because both threads perform a read-modify-write on the same word. CPU 0 (bind) CPU 1 (SIOCGSTAMPNS_NEW) -------------------------------- ---------------------------- read sk_flags = F read sk_flags = F compute F | BIT(SOCK_RCU_FREE) compute F | BIT(SOCK_TIMESTAMP) store F | BIT(SOCK_RCU_FREE) sk_add_node_rcu(sk, ...) store F | BIT(SOCK_TIMESTAMP) After the lost update, SOCK_RCU_FREE is clear while the socket is visible to lockless UDP receive lookups. sk_destruct() then frees the socket immediately instead of waiting for a RCU grace period, while the receive path still holds a reference-less pointer to it: BUG: KASAN: slab-use-after-free in ipv4_pktinfo_prepare+0x30/0x410 Read of size 8 at addr ffff888008806610 by task exploit/207 CPU: 0 UID: 1000 PID: 207 Comm: exploit Not tainted 6.12.95+ #1 ipv4_pktinfo_prepare+0x30/0x410 udp_queue_rcv_one_skb+0x51c/0x1180 udp_unicast_rcv_skb+0x109/0x350 ip_protocol_deliver_rcu+0x14b/0x310 ip_local_deliver_finish+0x29d/0x390 ip_local_deliver+0x24d/0x2a0 Only grab the socket lock when SOCK_TIMESTAMP has to be set, to keep the common case lockless.

In plain language

No plain-language summary for this CVE yet.

Exploitation

Where each signal puts this CVE on the scale from published to confirmed exploited.

EPSS3rd
CISA KEV

Not in the catalog. CISA has not confirmed exploitation.

Public exploits

No public exploit or proof of concept found in the sources we track.

EPSS

0.1% chance of exploitation activity in the next 30 days, which ranks it in the 3rd percentile of scored CVEs.

Exploit Prediction Scoring System, FIRST.org. A probability, not a confirmation.

Lifecycle

3 events over 1 day, from the signal feeds we watch.

  1. Record updated
  2. Publishedrecord updated

Affected products

Technical detail

CVSS 3.1 vector

Open in the CVSS calculator

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

Scored 7.8 by NVD.

How it is reached

  • Attack Vector LocalRequires local access to the vulnerable system (e.g. local login, malicious file)
  • Attack Complexity LowNo special conditions — the attack can be reliably reproduced
  • Privileges Required LowRequires basic user-level privileges
  • User Interaction NoneNo user interaction needed — fully automated exploitation

Scope

  • Scope UnchangedImpact is limited to the vulnerable component itself

Impact if exploited

  • Confidentiality HighTotal information disclosure — all data in the component is compromised
  • Integrity HighTotal loss of integrity — attacker can modify any data in the component
  • Availability HighTotal denial of service — the component is completely unavailable

Sources

References in the record

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In the news

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