Linux: Out-of-bounds Read
CVE-2026-52942 is a high-severity out-of-bounds read vulnerability in Linux, with a CVSS 3.1 base score of 7.1 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. The record lists versions 2e96e1bc9b4d5450e6c33f078e19a9bc1dda6c0b, d704ee9c7bc68a161684c51a7ac05b446dcf38d4, befb8968a2abdfa948d5600ea7f7a509a292a590 as the first without the flaw, so updating Linux to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.13% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Linux to 2e96e1bc9b4d5450e6c33f078e19a9bc1dda6c0b or d704ee9c7bc68a161684c51a7ac05b446dcf38d4 or befb8968a2abdfa948d5600ea7f7a509a292a590 or 8a81e336da685423f5b64aac4d571e63d674c52a, whichever matches your release line, or a later version.
- Update Linux Kernel to 5.15.210 or 6.1.176 or 6.6.143 or 6.12.94, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 7eb9282cd0efac08b8377cbd5037ba297c77e3f7 up to, but not including, 2e96e1bc9b4d5450e6c33f078e19a9bc1dda6c0b; 7eb9282cd0efac08b8377cbd5037ba297c77e3f7 up to, but not including, d704ee9c7bc68a161684c51a7ac05b446dcf38d4; 7eb9282cd0efac08b8377cbd5037ba297c77e3f7 up to, but not including, befb8968a2abdfa948d5600ea7f7a509a292a590; 7eb9282cd0efac08b8377cbd5037ba297c77e3f7 up to, but not including, 8a81e336da685423f5b64aac4d571e63d674c52a; 7eb9282cd0efac08b8377cbd5037ba297c77e3f7 up to, but not including, c38d41134085193efd5b237cf513ad5b3421a60d; 7eb9282cd0efac08b8377cbd5037ba297c77e3f7 up to, but not including, af1b7699466f6556b351fa25d3dc870abfb5d310; 7eb9282cd0efac08b8377cbd5037ba297c77e3f7 up to, but not including, 65ef7397eb9a296e91839f5fd10be96f23d332e7; 7eb9282cd0efac08b8377cbd5037ba297c77e3f7 up to, but not including, a84b6fedbc97078788be78dbdd7517d143ad1a77; and 1 more ranges | 2e96e1bc9b4d5450e6c33f078e19a9bc1dda6c0b, d704ee9c7bc68a161684c51a7ac05b446dcf38d4, befb8968a2abdfa948d5600ea7f7a509a292a590, 8a81e336da685423f5b64aac4d571e63d674c52a, c38d41134085193efd5b237cf513ad5b3421a60d, af1b7699466f6556b351fa25d3dc870abfb5d310 |
| Siemens | SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0) | V3.1.6 and later; V3.1.7 and later | Not stated |
| Siemens | SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0) | V3.1.6 and later; V3.1.7 and later | Not stated |
| Siemens | SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0) | V3.1.6 and later; V3.1.7 and later | Not stated |
| Siemens | SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AC0) | V3.1.6 and later; V3.1.7 and later | Not stated |
| Siemens | SIMATIC S7-1500 TM MFP - GNU/Linux subsystem | all versions | Not stated |
| Siemens | SIPLUS S7-1500 CPU 1518-4 PN/DP MFP (6AG1518-4AX00-4AC0) | V3.1.6 and later; V3.1.7 and later | Not stated |
| Linux | Linux Kernel | 2.6.36 up to, but not including, 5.15.210; 5.16 up to, but not including, 6.1.176; 6.2 up to, but not including, 6.6.143; 6.7 up to, but not including, 6.12.94; 6.13 up to, but not including, 6.18.36; 6.19 up to, but not including, 7.0.13; 7.1 | 5.15.210, 6.1.176, 6.6.143, 6.12.94, 6.18.36, 7.0.13 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- LocalThe attacker needs local access or must trick a user into running something.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- NoneNothing can be modified.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H. Scored by CNA.
Official description
In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_log: validate MAC header was set before dumping it The fallback path of dump_mac_header() guards the MAC header access only with "skb->mac_header != skb->network_header", without checking skb_mac_header_was_set(). When the MAC header is unset, mac_header is 0xffff, so the test passes and skb_mac_header(skb) returns skb->head + 0xffff, ~64 KiB past the buffer; the loop then reads dev->hard_header_len bytes out of bounds into the kernel log. This is reachable via the netdev logger: nf_log_unknown_packet() calls dump_mac_header() unconditionally, and an skb sent through AF_PACKET with PACKET_QDISC_BYPASS reaches the egress hook with mac_header still unset (__dev_queue_xmit(), which would reset it, is bypassed). Add the skb_mac_header_was_set() check the ARPHRD_ETHER path already uses, and replace the open-coded MAC header length test with skb_mac_header_len(). Only skbs with an unset MAC header are affected; valid ones are dumped as before. BUG: KASAN: slab-out-of-bounds in dump_mac_header (net/netfilter/nf_log_syslog.c:831) Read of size 1 at addr ffff88800ea49d3f by task exploit/148 Call Trace: kasan_report (mm/kasan/report.c:595) dump_mac_header (net/netfilter/nf_log_syslog.c:831) nf_log_netdev_packet (net/netfilter/nf_log_syslog.c:938 net/netfilter/nf_log_syslog.c:963) nf_log_packet (net/netfilter/nf_log.c:260) nft_log_eval (net/netfilter/nft_log.c:60) nft_do_chain (net/netfilter/nf_tables_core.c:285) nft_do_chain_netdev (net/netfilter/nft_chain_filter.c:307) nf_hook_slow (net/netfilter/core.c:619) nf_hook_direct_egress (net/packet/af_packet.c:257) packet_xmit (net/packet/af_packet.c:280) packet_sendmsg (net/packet/af_packet.c:3114) __sys_sendto (net/socket.c:2265)
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Out-of-bounds Read
The product reads data past the end, or before the beginning, of the intended buffer.
How developers prevent this class of flaw
- Use a language that provides appropriate memory abstractions.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
- git.kernel.org/stable/c/65ef7397eb9a296e91839f5fd10be96f23d332e7
- git.kernel.org/stable/c/8a81e336da685423f5b64aac4d571e63d674c52a
- git.kernel.org/stable/c/a84b6fedbc97078788be78dbdd7517d143ad1a77
- git.kernel.org/stable/c/af1b7699466f6556b351fa25d3dc870abfb5d310
- git.kernel.org/stable/c/befb8968a2abdfa948d5600ea7f7a509a292a590
- git.kernel.org/stable/c/c38d41134085193efd5b237cf513ad5b3421a60d
- git.kernel.org/stable/c/d704ee9c7bc68a161684c51a7ac05b446dcf38d4
Other references
Recent Out-of-bounds Read vulnerabilities
- 8.8 High severity
- 7.8 High severity
- 7.1 High severity
- 7.1 High severity
- 9.1 Critical severity
- 7.1 High severity
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