Linux Kernel up to 7.1.4 sockmap net/core/filter.c bpf_msg_pop_data integer overflow

CVSS Meta Temp Score
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CTI Interest Score
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6.2$0-$5k1.40

Summaryinfo

A vulnerability was found in Linux Kernel up to 7.1.4 and classified as critical. This impacts the function bpf_msg_pop_data of the file net/core/filter.c of the component sockmap. Such manipulation leads to integer overflow. This vulnerability is uniquely identified as CVE-2026-74256. The attack can be launched remotely. No exploit exists.

Detailsinfo

A vulnerability was found in Linux Kernel up to 7.1.4. It has been rated as critical. Affected by this issue is the function bpf_msg_pop_data of the file net/core/filter.c of the component sockmap. The manipulation with an unknown input leads to a integer overflow vulnerability. Using CWE to declare the problem leads to CWE-190. The product performs a calculation that can produce an integer overflow or wraparound, when the logic assumes that the resulting value will always be larger than the original value. This can introduce other weaknesses when the calculation is used for resource management or execution control. Impacted is availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: bpf, sockmap: fix integer overflow in bpf_msg_pop_data() bounds check start and len are u32, so u64 last = start + len; evaluates start + len in 32-bit and wraps before storing it in last. The bounds check if (start >= offset + l || last > msg->sg.size) return -EINVAL; can then be passed with an out-of-range start/len, after which the pop loop runs off the end of the scatterlist and sk_msg_shift_left() calls put_page() on the empty msg->sg.end slot: Oops: general protection fault, probably for non-canonical address 0xdffffc0000000001: 0000 [#1] SMP KASAN PTI KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f] RIP: 0010:sk_msg_shift_left net/core/filter.c:2957 [inline] RIP: 0010:____bpf_msg_pop_data net/core/filter.c:3103 [inline] RIP: 0010:bpf_msg_pop_data+0x753/0x1a10 net/core/filter.c:2984 Call Trace: <TASK> bpf_prog_4cc92c278f4d5d56+0x1b1/0x1e8 bpf_prog_run_pin_on_cpu+0x107/0x320 include/linux/filter.h:746 sk_psock_msg_verdict+0x357/0x7f0 net/core/skmsg.c:934 tcp_bpf_send_verdict net/ipv4/tcp_bpf.c:420 [inline] tcp_bpf_sendmsg+0x766/0x1ae0 net/ipv4/tcp_bpf.c:583 __sock_sendmsg+0x153/0x1c0 net/socket.c:802 __sys_sendto+0x326/0x430 net/socket.c:2265 __x64_sys_sendto+0xe3/0x100 net/socket.c:2268 do_syscall_64+0x14c/0x480 entry_SYSCALL_64_after_hwframe+0x77/0x7f </TASK> Widen the addition with a (u64) cast so the bound is evaluated in 64-bit and a len near U32_MAX no longer wraps below msg->sg.size. While here, change pop from int to u32. It counts bytes against the unsigned scatterlist lengths and can never be negative, so the signed type only invites sign-confusion in the pop loop.

The advisory is shared for download at git.kernel.org. This vulnerability is handled as CVE-2026-74256 since 08/15/2026. The exploitation is known to be easy. The attack may be launched remotely. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 08/15/2026).

Upgrading to version 5.10.261, 5.15.212, 6.1.178, 6.6.145, 6.12.97, 6.18.40, 7.1.5 or 7.2-rc1 eliminates this vulnerability. Applying the patch 9ef44ed6fb0c1db01cfcc3de432a33e719713eb5/d693c5ed67dabe1ccbf8dcea93075bdc9ffd4ca0/ba5cc05dae8fce237d191c7ea96b1107a791e548/c05a0ec1cdced622a1a0c7d85679fe02f31033ec/17eb9832a10db2f7a80cb429ca2bc5038445a943/fe09dd288722f1c749b7506c0b3e7841a7d85027/e09f7bd7273928b4089e6b71f8e992f2b356ca1b/a48802fb2cd2d1e23651989f8ff4d15e9d5dad54 is able to eliminate this problem.

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Productinfo

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 6.5
VulDB Meta Temp Score: 6.2

VulDB Base Score: 6.5
VulDB Temp Score: 6.2
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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💳💳💳💳💳💳
💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Integer overflow
CWE: CWE-190 / CWE-189
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 5.10.261/5.15.212/6.1.178/6.6.145/6.12.97/6.18.40/7.1.5/7.2-rc1
Patch: 9ef44ed6fb0c1db01cfcc3de432a33e719713eb5/d693c5ed67dabe1ccbf8dcea93075bdc9ffd4ca0/ba5cc05dae8fce237d191c7ea96b1107a791e548/c05a0ec1cdced622a1a0c7d85679fe02f31033ec/17eb9832a10db2f7a80cb429ca2bc5038445a943/fe09dd288722f1c749b7506c0b3e7841a7d85027/e09f7bd7273928b4089e6b71f8e992f2b356ca1b/a48802fb2cd2d1e23651989f8ff4d15e9d5dad54

Timelineinfo

08/15/2026 Advisory disclosed
08/15/2026 +0 days CVE reserved
08/15/2026 +0 days VulDB entry created
08/15/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-74256 (🔒)
GCVE (CVE): GCVE-0-2026-74256
GCVE (VulDB): GCVE-100-390212

Entryinfo

Created: 08/15/2026 08:28
Changes: 08/15/2026 08:28 (60)
Complete: 🔍
Cache ID: 216::103

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