Cyber Resilience

CVE-2024-26635

Linux Kernel 3.5 – 4.19.307

Published
18 March 2024
Modified
17 June 2026
Patch / advisory
CVSS Score v3.1 5.5
Click a component to see what it means
Raw vectorCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
EPSS Score 0.0024 15th percentile
Risk Priority 42 floored blend · peak EPSS

Summary

CVE-2024-26635 is a medium-severity Missing Initialization of Resource (CWE-909) vulnerability in Linux Linux Kernel. Its CVSS base score is 5.5 (Medium).

Operationally, ranked at the 15th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SA-15 (Development Process, Standards, and Tools) — see the control section below for these in your framework.

EU & UK References

Vulnerability Data

In the Linux kernel, the following vulnerability has been resolved: llc: Drop support for ETH_P_TR_802_2. syzbot reported an uninit-value bug below. [0] llc supports ETH_P_802_2 (0x0004) and used to support ETH_P_TR_802_2 (0x0011), and syzbot abused the latter to trigger the…

more

bug. write$tun(r0, &(0x7f0000000040)={@val={0x0, 0x11}, @val, @mpls={[], @llc={@snap={0xaa, 0x1, ')', "90e5dd"}}}}, 0x16) llc_conn_handler() initialises local variables {saddr,daddr}.mac based on skb in llc_pdu_decode_sa()/llc_pdu_decode_da() and passes them to __llc_lookup(). However, the initialisation is done only when skb->protocol is htons(ETH_P_802_2), otherwise, __llc_lookup_established() and __llc_lookup_listener() will read garbage. The missing initialisation existed prior to commit 211ed865108e ("net: delete all instances of special processing for token ring"). It removed the part to kick out the token ring stuff but forgot to close the door allowing ETH_P_TR_802_2 packets to sneak into llc_rcv(). Let's remove llc_tr_packet_type and complete the deprecation. [0]: BUG: KMSAN: uninit-value in __llc_lookup_established+0xe9d/0xf90 __llc_lookup_established+0xe9d/0xf90 __llc_lookup net/llc/llc_conn.c:611 [inline] llc_conn_handler+0x4bd/0x1360 net/llc/llc_conn.c:791 llc_rcv+0xfbb/0x14a0 net/llc/llc_input.c:206 __netif_receive_skb_one_core net/core/dev.c:5527 [inline] __netif_receive_skb+0x1a6/0x5a0 net/core/dev.c:5641 netif_receive_skb_internal net/core/dev.c:5727 [inline] netif_receive_skb+0x58/0x660 net/core/dev.c:5786 tun_rx_batched+0x3ee/0x980 drivers/net/tun.c:1555 tun_get_user+0x53af/0x66d0 drivers/net/tun.c:2002 tun_chr_write_iter+0x3af/0x5d0 drivers/net/tun.c:2048 call_write_iter include/linux/fs.h:2020 [inline] new_sync_write fs/read_write.c:491 [inline] vfs_write+0x8ef/0x1490 fs/read_write.c:584 ksys_write+0x20f/0x4c0 fs/read_write.c:637 __do_sys_write fs/read_write.c:649 [inline] __se_sys_write fs/read_write.c:646 [inline] __x64_sys_write+0x93/0xd0 fs/read_write.c:646 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x44/0x110 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x63/0x6b Local variable daddr created at: llc_conn_handler+0x53/0x1360 net/llc/llc_conn.c:783 llc_rcv+0xfbb/0x14a0 net/llc/llc_input.c:206 CPU: 1 PID: 5004 Comm: syz-executor994 Not tainted 6.6.0-syzkaller-14500-g1c41041124bd #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/09/2023

CWE(s)

Related Threats

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CVE-2024-35905Same product: Debian Debian Linux
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Affected Assets

linux
linux kernel
6.8 · 3.5 — 4.19.307 · 4.20 — 5.4.269 · 5.5 — 5.10.210
debian
debian linux
10.0

Mitigating Controls

Mitigating Controls (NIST 800-53 r5) AI

Developer testing and evaluation can discover missing initialization through static analysis or test cases.

Documented development standards and processes can mandate initialization of critical resources.

Security engineering principles can require explicit resource initialization during design and coding.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure SDLC practices directly require proper resource initialization as part of coding standards and verification.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

finds

Security testing can detect missing initialization defects before deployment.

prevents

Secure development life cycle mandates initialization of resources before use.

prevents

Application security requirements can specify resource initialization checks.

prevents

Secure architecture principles include proper resource lifecycle management.

prevents

Secure coding standards explicitly require initialization of variables and resources.

none

Change management can enforce review of initialization logic during modifications.

References