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Fencer Vulns
medium 4.3

CVE-2025-27465 json

x86: Incorrect stubs exception handling for flags recovery

published 2025-07-16 15 mo ago modified 2026-06-17 4 mo ago also EUVD-2025-21593

cvss
4.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.7%
EPSS 0.7% chance of exploitation in 30 days, percentile 53%
public exploits
0
none known

Summary

Certain instructions need intercepting and emulating by Xen. In some cases Xen emulates the instruction by replaying it, using an executable stub. Some instructions may raise an exception, which is supposed to be handled gracefully. Certain replayed instructions have additional logic to set up and recover the changes to the arithmetic flags.

For replayed instructions where the flags recovery logic is used, the metadata for exception handling was incorrect, preventing Xen from handling the the exception gracefully, treating it as fatal instead.

Patch / fix

  • xen Debian 12 4.17.5+72-g01140da4e8-1
  • xen Debian 13 4.20.2+7-g1badcf5035-0+deb13u1
  • xen Debian 14 4.20.2+7-g1badcf5035-1

debian advisories DEBIAN-CVE-2025-27465

  • xen SLES for SAP 15 SP4, SLES 15 SP4-LTSS, SLE Micro 5.4 +5 more 4.16.7_02-150400.4.72.1
  • xen SLES for SAP 15 SP5, SLES 15 SP5-LTSS, SLE Micro 5.5 +2 more 4.17.5_10-150500.3.50.1
  • xen SLES for SAP 15 SP3, SLES 15 SP3-LTSS, SLE Micro 5.2 +3 more 4.14.6_26-150300.3.91.1
  • xen SLE Module for Server Applications 15 SP6, SLE Module for Basesystem 15 SP6, openSUSE Leap 15.6 4.18.5_04-150600.3.28.1
  • xen SLE Module for Server Applications 15 SP7, SLE Module for Basesystem 15 SP7 4.20.1_02-150700.3.8.1
  • xen SLES LTSS Extended Security 12 SP5, SLES 12 SP5-LTSS 4.12.4_62-3.130.1

suse advisories SUSE-SU-2025:02471-1SUSE-SU-2025:02326-1SUSE-SU-2025:02325-1SUSE-SU-2025:02319-1SUSE-SU-2025:02316-1SUSE-SU-2025:02315-1

  • xen openSUSE Tumbleweed 4.20.1_02-1.1

opensuse advisories openSUSE-SU-2025:15342-1

  • xen Alpine 3.20, Alpine 3.19 4.18.5-r1
  • xen Alpine 3.21 4.19.2-r2
  • xen Alpine 3.24, Alpine 3.23, Alpine 3.22 4.20.1-r0

alpine advisories ALPINE-CVE-2025-27465

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2025-27465 updated cvss 6.5

xen: Xen: Incorrect Exception Handling

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
15 mo ago

Exploit prediction

0.70% chance of exploitation in the next 30 days, higher than 53% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CISA ADP 3.1 4.3 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
CNA 3.1 4.3 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L

Affected products

  • Xen Xen

Classification

Weakness
  • CWE-755 Improper Handling of Exceptional Conditions

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.