7.8

CVE-2026-63817: linux

CVSS: 7.8v3.1HighAwaiting analysis
AliasesUBUNTU-CVE-2026-63817DEBIAN-CVE-2026-63817
Published 19-07-2026Last modified 17-08-2026
Open JSON

Vulnerability summary

CVE-2026-63817 is a high (CVSS 7.8) vulnerability in linux. EPSS estimates a 0.13% chance of exploitation in the next 30 days, higher than 2.5% of scored vulnerabilities.

Overall risk
31/100
0100
Medium · default modelHow is this calculated?
CVSS score
7.8/10
010
High · v3.1 (CVE.org)
EPSS score
0.13%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 22 · Related 21
MGASA-2026-0312OPENSUSE-SU-2026:11339-1USN-8726-1USN-8726-2USN-8726-3USN-8726-4

Timeline

  1. 19-07-2026
    PublishedVulnerability first disclosed.
  2. 17-08-2026
    Last modifiedVulnerability information updated.

Description

In the Linux kernel, the following vulnerability has been resolved: f2fs: validate compress cache inode only when enabled F2FS_COMPRESS_INO() uses NM_I(sbi)->max_nid as the synthetic inode number for the compressed page cache inode. That inode only exists when the compress_cache mount option is enabled. When compress_cache is disabled, max_nid is outside the valid inode range. A corrupted directory entry that points to ino == max_nid should therefore be rejected by f2fs_check_nid_range(). However, is_meta_ino() currently treats F2FS_COMPRESS_INO() as a meta inode unconditionally, so f2fs_iget() bypasses do_read_inode() and its nid range check, and instantiates a fake internal inode instead. Gate the compressed cache inode case on COMPRESS_CACHE, matching f2fs_init_compress_inode(). With compress_cache disabled, ino == max_nid now follows the normal inode path and is rejected as an out-of-range nid.

CVSS metrics

4 scores · 4 sources · 1 version

EPSS trend

Probability

0.13%

Chance of exploitation in the next 30 days

Percentile

3%

Versus all other CVEs

30-day change

0.00 pp

From 0.13% on 19-09-2026

19-09-202619-10-2026
EPSS score
0.13%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

No weakness data has been published for this record.

Affected systems

Ubuntu157 products
  • linuxAll versions (No fix recorded) | < 5.15.0-198.208 | < 6.8.0-147.147 | < 7.0.0-31.31
  • linux-allwinner-5.19All versions (No fix recorded)
  • linux-awsAll versions (No fix recorded) | < 5.15.0-1117.124 | < 6.8.0-1067.70 | < 7.0.0-1012.12
  • linux-aws-5.0All versions (No fix recorded)
  • linux-aws-5.11All versions (No fix recorded)
Debian1 product
  • linux< 6.1.177-1 | < 6.12.95-1 | < 7.1.3-1
Linux1 product
  • linux≥ 6ce19aff0b8cd386860855185c6cd79337fc4d2b, < fcc051d377a9701a452e7663a1a8223c26225df9 | ≥ 6ce19aff0b8cd386860855185c6cd79337fc4d2b, < 29115b8c9172d34e67ab26cc4f6c209b7a236d7a | ≥ 6ce19aff0b8cd386860855185c6cd79337fc4d2b, < 13e4b59d3a9413f66f116fa6c4828519b960a5ea | ≥ 6ce19aff0b8cd386860855185c6cd79337fc4d2b, < 16161444c30d8dff9428abbae42b72ce4e32a932 | ≥ 6ce19aff0b8cd386860855185c6cd79337fc4d2b, < 77f216ff9ce5cde8eed9f6d12707e906dffdc9f7 | ≥ 6ce19aff0b8cd386860855185c6cd79337fc4d2b, < 0969926d987bbde9a1aa49da317582ba37095805 | ≥ 6ce19aff0b8cd386860855185c6cd79337fc4d2b, < 5073c66a96a9c23c0c2533ed4ed06e42f9021208 | a23706426da9b611be5beae0f3faa260fb453b4e | ≥ 5.13.19, < 5.14 | 5.14

3 vendors · 159 products

References

31 links
Show all 31 references