High severity · published May 27, 2026
CVE-2026-45991
udf: fix partition descriptor append bookkeeping
7.8
CVSS
0.2%
EPSS
No
On KEV
Description
In the Linux kernel, the following vulnerability has been resolved: udf: fix partition descriptor append bookkeeping Mounting a crafted UDF image with repeated partition descriptors can trigger a heap out-of-bounds write in part_descs_loc[]. handle_partition_descriptor() deduplicates entries by partition number, but appended slots never record partnum. As a result duplicate Partition Descriptors are appended repeatedly and num_part_descs keeps growing. Once the table is full, the growth path still sizes the allocation from partnum even though inserts are indexed by num_part_descs. If partnum is already aligned to PART_DESC_ALLOC_STEP, ALIGN(partnum, step) can keep the old capacity and the next append writes past the end of the table. Store partnum in the appended slot and size growth from the next append count so deduplication and capacity tracking follow the same model.
CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 7% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
KE
Kernel · Linux
4.18.7 before 4.19; 4.19.1 before 6.6.140; 6.7 before 6.12.88; 6.13 before 7.0.4; 4.19; 4.19; +6 more · source: NVD
LI
Linux · Linux
ee4af50ca94f58afc3532662779b9cf80bbe27c8 before ad3c0c4400686f6f37b382aaa48fac2b9aefccbe; ee4af50ca94f58afc3532662779b9cf80bbe27c8 before 68013a9bd4c01acd42073715f00e1a1992f089ee; ee4af50ca94f58afc3532662779b9cf80bbe27c8 before e8474cfbac9ada2cdaa4eaedec22aadfa0f58559; ee4af50ca94f58afc3532662779b9cf80bbe27c8 before 058b451b1039f056d1362c4fec2229e522366ab0; ee4af50ca94f58afc3532662779b9cf80bbe27c8 before b5597bb83fc37b5b5da74a4453fa920b932cf39a; ee4af50ca94f58afc3532662779b9cf80bbe27c8 before 73df74544b55241dca5dd788523e6f5f10bd2b9b; +5 more · source: vendor