FKIE_CVE-2026-74589
Vulnerability from fkie_nvd - Published: 2026-08-22 16:16 - Updated: 2026-08-25 06:18
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved:
bpf, sockmap: Fix sk_redir use-after-free in send verdict
sk_psock_msg_verdict() takes a socket reference for psock->sk_redir.
tcp_bpf_send_verdict() copies that pointer while holding the source socket
lock, but does not take a reference for the local copy before dropping the
lock around tcp_bpf_sendmsg_redir().
When apply_bytes keeps the cached verdict active, another sendmsg() on the
same source socket can consume the remaining bytes and release the cached
reference while the first thread still holds only the raw local pointer:
CPU 0 CPU 1
sk_redir = psock->sk_redir
apply_bytes remains nonzero
release_sock(sk)
lock_sock(sk)
apply_bytes reaches zero
psock->sk_redir = NULL
release_sock(sk)
tcp_bpf_sendmsg_redir(sk_redir)
sock_put(sk_redir)
tcp_bpf_sendmsg_redir(sk_redir)
The final sock_put() can free sk_redir before CPU 0 dereferences it.
KASAN reported:
BUG: KASAN: slab-use-after-free in tcp_bpf_sendmsg_redir+0xf39/0x1020
Read of size 8 at addr ffff888108537090 by task poc/87
Call Trace:
tcp_bpf_sendmsg_redir+0xf39/0x1020
tcp_bpf_sendmsg+0x977/0x1a50
__sys_sendto+0x32c/0x3a0
__x64_sys_sendto+0xdb/0x1b0
Allocated by task 85:
sk_prot_alloc+0x56/0x210
sk_clone+0x6f/0x14b0
inet_csk_clone_lock+0x24/0x740
tcp_create_openreq_child+0x25/0x2710
tcp_v4_syn_recv_sock+0x10a/0xe00
Freed by task 0:
__kasan_slab_free+0x43/0x70
slab_free_after_rcu_debug+0xa6/0x1e0
rcu_core+0x50a/0x1850
Last potentially related work creation:
__sk_destruct+0x3da/0x540
sk_psock_destroy+0x81e/0xab0
process_one_work+0x63a/0x1070
Take a temporary socket reference while the source socket lock still
protects psock->sk_redir, and drop it after tcp_bpf_sendmsg_redir()
returns. This keeps each unlocked use independent of cached-verdict
ownership.
References
Impacted products
| Vendor | Product | Version |
|---|
{
"affected": [
{
"affectedData": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"net/ipv4/tcp_bpf.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "41b7da0cb72ca5aa1e62b68dab323d0791fc6bdf",
"status": "affected",
"version": "604326b41a6fb9b4a78b6179335decee0365cd8c",
"versionType": "git"
},
{
"lessThan": "9b4fbc371a6ecf1b4e43b5a629015cc0830d8de3",
"status": "affected",
"version": "604326b41a6fb9b4a78b6179335decee0365cd8c",
"versionType": "git"
},
{
"lessThan": "90a19b0894ba79a699b48cf44421b36fbd566e99",
"status": "affected",
"version": "604326b41a6fb9b4a78b6179335decee0365cd8c",
"versionType": "git"
},
{
"lessThan": "d192cff2a37d59206dabe6ec2e60ceac6271f274",
"status": "affected",
"version": "604326b41a6fb9b4a78b6179335decee0365cd8c",
"versionType": "git"
},
{
"lessThan": "4c9d9aa809c261dc0490a0e19d675f7e8e4c85bf",
"status": "affected",
"version": "604326b41a6fb9b4a78b6179335decee0365cd8c",
"versionType": "git"
},
{
"lessThan": "a14e4ef1d90c3418f01b3b6b8fd3a40a0a208a10",
"status": "affected",
"version": "604326b41a6fb9b4a78b6179335decee0365cd8c",
"versionType": "git"
},
{
"lessThan": "1cec526cf0a2227395f2c2f4b671cb052ff0b00e",
"status": "affected",
"version": "604326b41a6fb9b4a78b6179335decee0365cd8c",
"versionType": "git"
},
{
"lessThan": "a76624733730e541e4955fdecf506af2f6b20558",
"status": "affected",
"version": "604326b41a6fb9b4a78b6179335decee0365cd8c",
"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"net/ipv4/tcp_bpf.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "4.20"
},
{
"lessThan": "4.20",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.10.*",
"status": "unaffected",
"version": "5.10.265",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.15.*",
"status": "unaffected",
"version": "5.15.216",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"version": "6.1.183",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.152",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.104",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.45",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.1.*",
"status": "unaffected",
"version": "7.1.9",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix"
}
]
}
],
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf, sockmap: Fix sk_redir use-after-free in send verdict\n\nsk_psock_msg_verdict() takes a socket reference for psock-\u003esk_redir.\ntcp_bpf_send_verdict() copies that pointer while holding the source socket\nlock, but does not take a reference for the local copy before dropping the\nlock around tcp_bpf_sendmsg_redir().\n\nWhen apply_bytes keeps the cached verdict active, another sendmsg() on the\nsame source socket can consume the remaining bytes and release the cached\nreference while the first thread still holds only the raw local pointer:\n\n CPU 0 CPU 1\n sk_redir = psock-\u003esk_redir\n apply_bytes remains nonzero\n release_sock(sk)\n lock_sock(sk)\n apply_bytes reaches zero\n psock-\u003esk_redir = NULL\n release_sock(sk)\n tcp_bpf_sendmsg_redir(sk_redir)\n sock_put(sk_redir)\n tcp_bpf_sendmsg_redir(sk_redir)\n\nThe final sock_put() can free sk_redir before CPU 0 dereferences it.\n\nKASAN reported:\n\n BUG: KASAN: slab-use-after-free in tcp_bpf_sendmsg_redir+0xf39/0x1020\n Read of size 8 at addr ffff888108537090 by task poc/87\n Call Trace:\n tcp_bpf_sendmsg_redir+0xf39/0x1020\n tcp_bpf_sendmsg+0x977/0x1a50\n __sys_sendto+0x32c/0x3a0\n __x64_sys_sendto+0xdb/0x1b0\n Allocated by task 85:\n sk_prot_alloc+0x56/0x210\n sk_clone+0x6f/0x14b0\n inet_csk_clone_lock+0x24/0x740\n tcp_create_openreq_child+0x25/0x2710\n tcp_v4_syn_recv_sock+0x10a/0xe00\n Freed by task 0:\n __kasan_slab_free+0x43/0x70\n slab_free_after_rcu_debug+0xa6/0x1e0\n rcu_core+0x50a/0x1850\n Last potentially related work creation:\n __sk_destruct+0x3da/0x540\n sk_psock_destroy+0x81e/0xab0\n process_one_work+0x63a/0x1070\n\nTake a temporary socket reference while the source socket lock still\nprotects psock-\u003esk_redir, and drop it after tcp_bpf_sendmsg_redir()\nreturns. This keeps each unlocked use independent of cached-verdict\nownership."
}
],
"id": "CVE-2026-74589",
"lastModified": "2026-08-25T06:18:33.760",
"metrics": {
"cvssMetricV31": [
{
"cvssData": {
"attackComplexity": "LOW",
"attackVector": "LOCAL",
"availabilityImpact": "HIGH",
"baseScore": 8.4,
"baseSeverity": "HIGH",
"confidentialityImpact": "HIGH",
"integrityImpact": "HIGH",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
"version": "3.1"
},
"exploitabilityScore": 2.5,
"impactScore": 5.9,
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"type": "Secondary"
}
]
},
"published": "2026-08-22T16:16:31.097",
"references": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/1cec526cf0a2227395f2c2f4b671cb052ff0b00e"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/41b7da0cb72ca5aa1e62b68dab323d0791fc6bdf"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/4c9d9aa809c261dc0490a0e19d675f7e8e4c85bf"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/90a19b0894ba79a699b48cf44421b36fbd566e99"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/9b4fbc371a6ecf1b4e43b5a629015cc0830d8de3"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/a14e4ef1d90c3418f01b3b6b8fd3a40a0a208a10"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/a76624733730e541e4955fdecf506af2f6b20558"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/d192cff2a37d59206dabe6ec2e60ceac6271f274"
}
],
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Received"
}
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
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.
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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.
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.
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