7.8

CVE-2026-74582: packet: use consistent hard_header_len in non-ring send paths

Received
AliasesRHSA-2026:63537UBUNTU-CVE-2026-74582DEBIAN-CVE-2026-74582
Published 21-08-2026Last modified 16-10-2026

Vulnerability summary

CVE-2026-74582 is a high (CVSS 7.8) vulnerability in linux. EPSS estimates a 0.12% chance of exploitation in the next 30 days, higher than 1.8% of scored vulnerabilities.

Priority
Routine

Not severe (CVSS 7.8, local access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
7.8/10
010
High · v3.1 (CVE.org)
EPSS score
0.12%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 29 · Related 18
MGASA-2026-0506MGASA-2026-0542OPENSUSE-SU-2026:21910-1RHSA-2026:60484RHSA-2026:60486RHSA-2026:62609

Timeline

  1. 21-08-2026
    PublishedVulnerability first disclosed.
  2. 16-10-2026
    Last modifiedVulnerability information updated.

Description

In the Linux kernel, the following vulnerability has been resolved: packet: use consistent hard_header_len in non-ring send paths packet_snd() reads dev->hard_header_len multiple times while allocating and constructing an skb. Device reconfiguration can change this value concurrently, for example through bonding device type changes. For SOCK_RAW, packet_snd() can save a larger value in reserve and later allocate headroom using a smaller value. Moving skb->data back by reserve then places it before skb->head, and the following copy from userspace can attempt an out-of-bounds write. packet_sendmsg_spkt() has the same issue because it calculates its reservation and header offset from separate reads before dropping the RCU read lock to allocate the skb. Add LL_RESERVED_SPACE_EX() for callers that already saved a header length. Read hard_header_len once in packet_snd() and use it for allocation and construction. In packet_sendmsg_spkt(), preserve the allocation-time value through the device lookup retry. The separate SOCK_DGRAM consistency problem between hard_header_len and header_ops->create is not addressed here.

CVSS metrics

5 scores · 5 sources · 1 version

EPSS trend

Probability

0.12%

Chance of exploitation in the next 30 days

Percentile

2%

Versus all other CVEs

30-day change

No change 0.00 pp

From 0.12% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

No weakness data has been published for this record.

Affected systems

Version check

Known conditions: local access, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.

Ubuntu169 products
  • linuxAll versions (No fix recorded)
  • linux-allwinner-5.19All versions (No fix recorded)
  • linux-awsAll versions (No fix recorded)
  • linux-aws-5.0All versions (No fix recorded)
  • linux-aws-5.11All versions (No fix recorded)
Redhat25 products
  • bpftool< 0:4.18.0-477.165.1.el8_8
  • bpftool-debuginfo< 0:4.18.0-477.165.1.el8_8
  • kernel< 0:4.18.0-477.165.1.el8_8
  • kernel-abi-stablelists< 0:4.18.0-477.165.1.el8_8
  • kernel-core< 0:4.18.0-477.165.1.el8_8
Debian2 products
  • linux< 6.1.187-1 | < 6.12.105-1 | < 7.1.9-1
  • linux-6.12< 6.12.107-1~deb12u1
Linux1 product
  • linux≥ b84bbaf7a6c8cca24f8acf25a2c8e46913a947ba, < bcd4df60ac9481b1ceffdfe5ec38fe51dcaae812 | ≥ b84bbaf7a6c8cca24f8acf25a2c8e46913a947ba, < 78a47127e33c340bc6d38dcc4552a094b4f5cc77 | ≥ b84bbaf7a6c8cca24f8acf25a2c8e46913a947ba, < 142e287b3a25cfe909215177c23243e7fc5ae2b1 | ≥ b84bbaf7a6c8cca24f8acf25a2c8e46913a947ba, < 91f041451f967cd87ed722a8f43c0b767a64f1a0 | ≥ b84bbaf7a6c8cca24f8acf25a2c8e46913a947ba, < 9052756290962ffb9a661bcf319e92dedaaedfed | ≥ b84bbaf7a6c8cca24f8acf25a2c8e46913a947ba, < 5bb10753d428aadfc356a2bfe9acea09c82a62ec | ≥ b84bbaf7a6c8cca24f8acf25a2c8e46913a947ba, < b06b6fce6d7deaf7238e09b48ce3b1125ff41acd | ≥ b84bbaf7a6c8cca24f8acf25a2c8e46913a947ba, < 03390aa32e669cc4ecd7d34108e2e1afc13d689d | d9fb8cc230b2a4757e9fe4f81468f81212d4deaa | 6190cce26e40bf71c4d375b21eea74bb07b6a0f3 | 01a658c1b9d4b5393c38d5a92d9112ab1425382a | 8809ae6747e760e6f1d2453ceb08c9bcc4939766 | ≥ 4.4.133, < 4.5 | ≥ 4.9.103, < 4.10 | ≥ 4.14.44, < 4.15 | ≥ 4.16.12, < 4.17 | 4.17

4 vendors · 197 products

References

19 links
Show all 19 references