How severe is CVE-2018-15857?

CVE-2018-15857 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2018-15857 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (36th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2018-15857?

CVE-2018-15857 primarily affects Xkbcommon Libxkbcommon. In total, 5 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2018-15857?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2018-15857 published?

CVE-2018-15857 was published on 2018-08-25 and last updated on 2026-06-17.

CVE-2018-15857

CVE-2018-15857 is a high-severity vulnerability in Xkbcommon Libxkbcommon with a CVSS 3.x base score of 7.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-416.

Key facts

Severity: High (CVSS 3.x base score 7.8)
CVSS v2: 4.6
EPSS exploit prediction: 0% (36th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-416
Affected product: Xkbcommon Libxkbcommon
Published: 2018-08-25
Last modified: 2026-06-17

Description

An invalid free in ExprAppendMultiKeysymList in xkbcomp/ast-build.c in xkbcommon before 0.8.1 could be used by local attackers to crash xkbcommon keymap parsers or possibly have unspecified other impact by supplying a crafted keymap file.

Frequently asked questions

What is CVE-2018-15857?: An invalid free in ExprAppendMultiKeysymList in xkbcomp/ast-build.c in xkbcommon before 0.8.1 could be used by local attackers to crash xkbcommon keymap parsers or possibly have unspecified other impact by supplying a crafted keymap file.
How severe is CVE-2018-15857?: CVE-2018-15857 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2018-15857 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (36th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2018-15857?: CVE-2018-15857 primarily affects Xkbcommon Libxkbcommon. In total, 5 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2018-15857?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2018-15857 published?: CVE-2018-15857 was published on 2018-08-25 and last updated on 2026-06-17.

References

Affected products (5)

cpe:2.3:a:xkbcommon:libxkbcommon:*:*:*:*:*:*:*:*
cpe:2.3:a:xkbcommon:xkbcommon:*:*:*:*:*:*:*:*
cpe:2.3:o:canonical:ubuntu_linux:14.04:*:*:*:lts:*:*:*
cpe:2.3:o:canonical:ubuntu_linux:16.04:*:*:*:lts:*:*:*
cpe:2.3:o:canonical:ubuntu_linux:18.04:*:*:*:lts:*:*:*

More vulnerabilities in Xkbcommon Libxkbcommon

CVE-2018-15864 — Medium (CVSS 5.5): Unchecked NULL pointer usage in resolve_keysym in xkbcomp/parser.y in xkbcommon before 0.8.2 could be used by local…
CVE-2018-15863 — Medium (CVSS 5.5): Unchecked NULL pointer usage in ResolveStateAndPredicate in xkbcomp/compat.c in xkbcommon before 0.8.2 could be used by…
CVE-2018-15862 — Medium (CVSS 5.5): Unchecked NULL pointer usage in LookupModMask in xkbcomp/expr.c in xkbcommon before 0.8.2 could be used by local…
CVE-2018-15861 — Medium (CVSS 5.5): Unchecked NULL pointer usage in ExprResolveLhs in xkbcomp/expr.c in xkbcommon before 0.8.2 could be used by local…
CVE-2018-15859 — Medium (CVSS 5.5): Unchecked NULL pointer usage when parsing invalid atoms in ExprResolveLhs in xkbcomp/expr.c in xkbcommon before 0.8.2…
CVE-2018-15858 — Medium (CVSS 5.5): Unchecked NULL pointer usage when handling invalid aliases in CopyKeyAliasesToKeymap in xkbcomp/keycodes.c in xkbcommon…

All CVEs affecting Xkbcommon Libxkbcommon →

Other CWE-416 (Use After Free) vulnerabilities

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CVE-2026-4725 — Critical (CVSS 10.0): Sandbox escape due to use-after-free in the Graphics: Canvas2D component. This vulnerability was fixed in Firefox 149…
CVE-2026-4688 — Critical (CVSS 10.0): Sandbox escape due to use-after-free in the Disability Access APIs component. This vulnerability was fixed in Firefox…
CVE-2025-24085 — Critical (CVSS 10.0): A use after free issue was addressed with improved memory management. This issue is fixed in iOS 18.3 and iPadOS 18.3,…
CVE-2024-43102 — Critical (CVSS 10.0): Concurrent removals of certain anonymous shared memory mappings by using the UMTX_SHM_DESTROY sub-request of…
CVE-2021-32495 — Critical (CVSS 10.0): Radare2 has a use-after-free vulnerability in pyc parser's get_none_object function. Attacker can read freed memory…

Browse all CWE-416 (Use After Free) vulnerabilities →