All vulnerabilities
CVE-2026-98403

Linux: s390/boot: Avoid IPL parameter append past command line

Linux LinuxOperating systems
Open in ThreatlineRecord JSON
CVSS
NoneNot scored
ExploitationNo known exploitationNot in CISA KEV, which does not prove it is unexploitedCISA KEV
Exploit odds (EPSS)0.21%Chance of exploitation activity in the next 30 days, higher than 10% of CVEs. Scored 23 Oct 2026FIRST EPSS
Fixed in73eec5a0d55916d7e1115f5d03a7ffc06d6215cfAlso 8d11bfec8666f8409fac9072e9c25b691d3e30acCVE List
Published14 Oct 2026Updated 19 Oct 2026CVE List

What fixes it

  • 73eec5a0d55916d7e1115f5d03a7ffc06d6215cfLinuxCVE List
  • 8d11bfec8666f8409fac9072e9c25b691d3e30acLinuxCVE List

A fixed version on one release line is not the upgrade target for every line. Check your exact version and any vendor backports.

Description

In the Linux kernel, the following vulnerability has been resolved:

s390/boot: Avoid IPL parameter append past command line

A command line may occupy all but the terminating byte of COMMAND_LINE_SIZE. In that case append_ipl_block_parm() passes a zero size to the IPL parameter conversion helpers and points the destination one byte past early_command_line. The helpers subtract one from the unsigned size and write the converted parameter outside the command line buffer.

Convert the IPL parameter in the command line parsing buffer first. A parameter beginning with '=' can then replace the existing command line regardless of its length, while other parameters are appended only when space remains.

Text from CVE List

Affected versions 10

  • Linuxaffected: 5ecb2da660ab8eddafe059a6a8a708465db89ca2 before af9866021a00ab9eeacf0c33ee73f3d134b4ed70CVE List
  • Linuxaffected: 5ecb2da660ab8eddafe059a6a8a708465db89ca2 before 73eec5a0d55916d7e1115f5d03a7ffc06d6215cfCVE List
  • Linuxaffected: 5ecb2da660ab8eddafe059a6a8a708465db89ca2 before 8d11bfec8666f8409fac9072e9c25b691d3e30acCVE List
  • Linuxaffected: 5ecb2da660ab8eddafe059a6a8a708465db89ca2 before d76181dfabdaa720703167393704efacba343442CVE List
  • Linuxaffected: 5.16CVE List
  • Linuxunaffected: all versions before 5.16CVE List
  • Linuxunaffected: 6.12.112 through 6.12.*CVE List
  • Linuxunaffected: 6.18.53 through 6.18.*CVE List
  • Linuxunaffected: 7.2.7 through 7.2.*CVE List
  • Linuxunaffected: 7.3CVE List

References 4