CVE-2026-89557md: do overflow check for sb->bblog_shift in super_1_load()
- 7.8HighCVSS base score
- 0.17%Exploitation in 30 daysEPSS · top 94% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
In the Linux kernel, the following vulnerability has been resolved: md: do overflow check for sb->bblog_shift in super_1_load() In super_1_load(), sb->bblog_shift is an __u8 type value loaded from on- disk superblock. It is used for badblocks API badblocks_set() by the following sequence, 1930 rdev->badblocks.shift = sb->bblog_shift; 1931 for (i = 0 ; i < (sectors << (9-3)) ; i++, bbp++) { 1932 u64 bb = le64_to_cpu(*bbp); 1933 int count = bb & (0x3ff); 1934 u64 sector = bb >> 10; 1935 sector <<= sb->bblog_shift; 1936 count <<= sb->bblog_shift; 1937 if (bb + 1 == 0) 1938 break; 1939 if (!badblocks_set(&rdev->badblocks, sector, count, 1)) 1940 return -EINVAL; 1941 } bb->bblog_shit is in range of 0-255, variable sector is 64bit width, for an invalid bb->bblog_shit, it is possible to make sector be overflowed by the following calculation, 1935 sector <<= sb->bblog_shift; Then in turn when call badblocks_set() at line 1939 with the invalid rdev->badblocks.shift set at line 1930, may result an overflow inside _badblocks_clear() in block/badblocks.c. Although there are many places to call badblocks APIs, the non-zero shift value is only used in super_1_load(), other places always use 0 as the shift value. Therefore it is unnecessary to do a general shift value overflow check inside badblock API, and just check here as the caller. This may avoid unnecessary check, make the badblocks API code more simple and elegant.
Timeline
ID reserved
By Linux
Published
- 38 days later
· 38 days later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| LinuxCNA (assigner) | 3.1 | High7.8 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
| NVDNVD · Received | 3.1 | High7.8 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
- EPSS (exploitation in 30 days)
- 0.17% · top 94% of all CVEs (13 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: total
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.8.
Affected products
- affected 2699b67223aca6b1450fc2f72e40fada952afc85 – < 94c820d99a4305d4ded41a97ed37ec7d26c56e7f
- affected 2699b67223aca6b1450fc2f72e40fada952afc85 – < 573fb68105fdc6a127ba6069e58a0d2aff3c9f93
- affected 2699b67223aca6b1450fc2f72e40fada952afc85 – < 323f3a056dbccb39a642ebde642044a680f3a6d6
- affected 2699b67223aca6b1450fc2f72e40fada952afc85 – < 0a03f9541c06fda64301dcf94f376f07ce2cc396
- affected 2699b67223aca6b1450fc2f72e40fada952afc85 – < 75d15738fd33a782606d0dc80cfeff47edf2ddd8
- affected 2699b67223aca6b1450fc2f72e40fada952afc85 – < 3b097416b4cff77285c1f472fc2c4058d8a7554f
- affected 2699b67223aca6b1450fc2f72e40fada952afc85 – < df7d4d011d5ace20699ea948712f09f9ac08924f
- affected 2699b67223aca6b1450fc2f72e40fada952afc85 – < 35d522bd32462afcf1981dab6da8a9256c26c1e0
- affected 3.1
- unaffected < 3.1
- unaffected 5.10.270 – ≤ 5.10.*
- unaffected 5.15.221 – ≤ 5.15.*
- unaffected 6.1.188 – ≤ 6.1.*
- unaffected 6.6.157 – ≤ 6.6.*
- unaffected 6.12.109 – ≤ 6.12.*
- unaffected 6.18.50 – ≤ 6.18.*
- unaffected 7.2.4 – ≤ 7.2.*
- unaffected 7.3 – ≤ *
References
References8
- https://git.kernel.org/stable/c/94c820d99a4305d4ded41a97ed37ec7d26c56e7f (opens in a new tab)
- https://git.kernel.org/stable/c/573fb68105fdc6a127ba6069e58a0d2aff3c9f93 (opens in a new tab)
- https://git.kernel.org/stable/c/323f3a056dbccb39a642ebde642044a680f3a6d6 (opens in a new tab)
- https://git.kernel.org/stable/c/0a03f9541c06fda64301dcf94f376f07ce2cc396 (opens in a new tab)
- https://git.kernel.org/stable/c/75d15738fd33a782606d0dc80cfeff47edf2ddd8 (opens in a new tab)
- https://git.kernel.org/stable/c/3b097416b4cff77285c1f472fc2c4058d8a7554f (opens in a new tab)
- https://git.kernel.org/stable/c/df7d4d011d5ace20699ea948712f09f9ac08924f (opens in a new tab)
- https://git.kernel.org/stable/c/35d522bd32462afcf1981dab6da8a9256c26c1e0 (opens in a new tab)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-76468 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
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[](https://cveledger.app/cve/CVE-2026-89557)Record last updated .