4.3

CVE-2026-79603: Unconditionally do TLB flushing ahead of page scrubbing

Awaiting analysis
AliasesALPINE-CVE-2026-79603UBUNTU-CVE-2026-79603DEBIAN-CVE-2026-79603
Published 08-09-2026Last modified 08-09-2026

Vulnerability summary

CVE-2026-79603 is a medium (CVSS 4.3) vulnerability in xen. EPSS estimates a 0.22% chance of exploitation in the next 30 days, higher than 12.8% of scored vulnerabilities.

Priority
Routine

Not severe (CVSS 4.3, network access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
4.3/10
010
Medium · v3.1 (CVE.org)
EPSS score
0.22%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 4 · Related 4
OPENSUSE-SU-2026:11738-1SUSE-SU-2026:4087-1SUSE-SU-2026:4088-1SUSE-SU-2026:4090-1

Timeline

  1. 08-09-2026
    PublishedVulnerability first disclosed.
  2. 08-09-2026
    Last modifiedVulnerability information updated.

Description

x86 PV guests can free memory pages while still keeping a stale TLB entry pointing to them. A TLB flush is only issued by Xen (if needed) when the page is re-used. Since it's possible for the page to be scrubbed ahead of the TLB flush, there's a window where a PV guest can modify an already scrubbed page.

CVSS metrics

5 scores · 5 sources · 1 version

EPSS trend

Probability

0.22%

Chance of exploitation in the next 30 days

Percentile

13%

Versus all other CVEs

30-day change

No change 0.00 pp

From 0.22% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: network-reachable, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.

Alpine1 product
  • xen< 4.19.6-r1 | < 4.20.4-r1 | < 4.21.2-r1
Debian1 product
  • xenAll versions (No fix recorded) | < 4.20.4+39-gf1e1321c87-0+deb13u1 | < 4.20.4+39-gf1e1321c87-1
Ubuntu1 product
  • xenAll versions (No fix recorded)

3 vendors · 3 products

References

7 links