CVE-2016-1521

CVE-2016-1521 is a high-severity vulnerability in Sil Graphite2 with a CVSS 3.x base score of 8.8. 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-119.

Key facts

Description

The directrun function in directmachine.cpp in Libgraphite in Graphite 2 1.2.4, as used in Mozilla Firefox before 43.0 and Firefox ESR 38.x before 38.6.1, does not validate a certain skip operation, which allows remote attackers to execute arbitrary code, obtain sensitive information, or cause a denial of service (out-of-bounds read and application crash) via a crafted Graphite smart font.

Frequently asked questions

What is CVE-2016-1521?
The directrun function in directmachine.cpp in Libgraphite in Graphite 2 1.2.4, as used in Mozilla Firefox before 43.0 and Firefox ESR 38.x before 38.6.1, does not validate a certain skip operation, which allows remote attackers to execute arbitrary code, obtain sensitive information, or cause a denial of service (out-of-bounds read and application crash) via a crafted Graphite smart font.
How severe is CVE-2016-1521?
CVE-2016-1521 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2016-1521 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 4% (89th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2016-1521?
CVE-2016-1521 primarily affects Sil Graphite2. In total, 19 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2016-1521?
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-2016-1521 published?
CVE-2016-1521 was published on 2016-02-13 and last updated on 2026-06-17.

References

Affected products (19)

More vulnerabilities in Sil Graphite2

All CVEs affecting Sil Graphite2 →

Other CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer) vulnerabilities

Browse all CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer) vulnerabilities →