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VulnerabilityPublished Updated

CVE-2025-71109: Linux kernel · MIPS: ftrace: Fix memory corruption when kernel is located beyond 32 bits

Affects Linux kernelSource GCVE Database

0
Authoritative record:CVE-2025-71109· High 7.1

Not known to be exploited · CVSS 7.1 High · fixed in 6.8.0-1052.55~22.04.1 : patch Linux kernel soon.

Data as of 26 Oct 2026, 12:55 UTC

CVSS 3.1 base score
7.1High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.2% chance of exploitation in 30 days – higher than 13% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 6.8.0-1052.55~22.04.1, 6.8.0-1059.65~22.04.1, 6.8.0-1058.65~22.04.1 +43
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 14 Jan 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
Ubuntu 25.10linuxpkg:deb/ubuntu/linux?arch=source&distro=questingOther threatsAffected
  • <6.17.0-22.22
Fixed in
  • 6.17.0-22.22
Ubuntu 25.10linux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=questingOther threatsAffected
  • <6.17.0-1012.12
Fixed in
  • 6.17.0-1012.12
Ubuntu 25.10linux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=questingOther threatsAffected
  • <6.17.0-1013.13
Fixed in
  • 6.17.0-1013.13
Ubuntu 25.10linux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=questingOther threatsAffected
  • 6.17.0-1003.3 – 6.17.0-1017.17
10 affected builds
Fixed in–
Ubuntu 25.10linux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=questingOther threatsAffected
  • <6.17.0-1012.12
Fixed in
  • 6.17.0-1012.12
Ubuntu 25.10linux-oraclepkg:deb/ubuntu/linux-oracle?arch=source&distro=questingOther threatsAffected
  • <6.17.0-1011.11
Fixed in
  • 6.17.0-1011.11

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

Description

In the Linux kernel, the following vulnerability has been resolved: MIPS: ftrace: Fix memory corruption when kernel is located beyond 32 bits Since commit e424054000878 ("MIPS: Tracing: Reduce the overhead of dynamic Function Tracer"), the macro UASM_i_LA_mostly has been used, and this macro can generate more than 2 instructions. At the same time, the code in ftrace assumes that no more than 2 instructions can be generated, which is why it stores them in an int[2] array. However, as previously noted, the macro UASM_i_LA_mostly (and now UASM_i_LA) causes a buffer overflow when _mcount is beyond 32 bits. This leads to corruption of the variables located in the __read_mostly section. This corruption was observed because the variable __cpu_primary_thread_mask was corrupted, causing a hang very early during boot. This fix prevents the corruption by avoiding the generation of instructions if they could exceed 2 instructions in length. Fortunately, insn_la_mcount is only used if the instrumented code is located outside the kernel code section, so dynamic ftrace can still be used, albeit in a more limited scope. This is still preferable to corrupting memory and/or crashing the kernel.

References

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