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Fencer Intel
low 3.3

CVE-2015-2877 json

Kernel Samepage Merging (KSM) in the Linux kernel 2.6.32 through 4.x does not prevent use of a write-timing side channel, which allows gues…

published 2017-03-03 9 y ago modified 2026-06-17 4 mo ago also EUVD-2015-2965

cvss
3.3
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.9%
EPSS 0.9% chance of exploitation in 30 days, percentile 61%
public exploits
0
none known

Summary

Kernel Samepage Merging (KSM) in the Linux kernel 2.6.32 through 4.x does not prevent use of a write-timing side channel, which allows guest OS users to defeat the ASLR protection mechanism on other guest OS instances via a Cross-VM ASL INtrospection (CAIN) attack. NOTE: the vendor states "Basically if you care about this attack vector, disable deduplication." Share-until-written approaches for memory conservation among mutually untrusting tenants are inherently detectable for information disclosure, and can be classified as potentially misunderstood behaviors rather than vulnerabilities

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-2015-2877 updated cvss 2.1

Kernel: Cross-VM ASL INtrospection (CAIN)

  • Red Hat Enterprise Linux 4 kernel Red Hat Enterprise Linux 5 kernel Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, python-perf, kernel-kdump, kernel-tools, +3 more
    affected: no fix planned “Will not fix”

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

Exploit prediction

0.94% chance of exploitation in the next 30 days, higher than 61% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
NVD 3.1 3.3 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
NVD 2.0 2.1 AV:L/AC:L/Au:N/C:P/I:N/A:N

Classification

Weakness
  • CWE-200 Exposure of Sensitive Information to an Unauthorized Actor
Technology feeds

References

Sources

Fencer Intel 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.