How severe is CVE-2018-15859?

CVE-2018-15859 has a CVSS 3.x base score of 5.5, rated medium severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2018-15859 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (41st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2018-15859?

CVE-2018-15859 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-2018-15859?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2018-15859 published?

CVE-2018-15859 was published on 2018-08-25 and last updated on 2026-06-17.

CVE-2018-15859

CVE-2018-15859 is a medium-severity vulnerability in Xkbcommon Libxkbcommon with a CVSS 3.x base score of 5.5. 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-476.

Key facts

Severity: Medium (CVSS 3.x base score 5.5)
CVSS v2: 2.1
EPSS exploit prediction: 1% (41st percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-476
Affected product: Xkbcommon Libxkbcommon
Published: 2018-08-25
Last modified: 2026-06-17

Description

Unchecked NULL pointer usage when parsing invalid atoms in ExprResolveLhs in xkbcomp/expr.c in xkbcommon before 0.8.2 could be used by local attackers to crash (NULL pointer dereference) the xkbcommon parser by supplying a crafted keymap file, because lookup failures are mishandled.

Frequently asked questions

What is CVE-2018-15859?: Unchecked NULL pointer usage when parsing invalid atoms in ExprResolveLhs in xkbcomp/expr.c in xkbcommon before 0.8.2 could be used by local attackers to crash (NULL pointer dereference) the xkbcommon parser by supplying a crafted keymap file, because lookup failures are mishandled.
How severe is CVE-2018-15859?: CVE-2018-15859 has a CVSS 3.x base score of 5.5, rated medium severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2018-15859 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (41st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2018-15859?: CVE-2018-15859 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-2018-15859?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2018-15859 published?: CVE-2018-15859 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-2018-15857 — High (CVSS 7.8): An invalid free in ExprAppendMultiKeysymList in xkbcomp/ast-build.c in xkbcommon before 0.8.1 could be used by local…
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-2018-15858 — 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 →

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Browse all CWE-476 (NULL Pointer Dereference) vulnerabilities →