How severe is CVE-2016-9954?

CVE-2016-9954 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2016-9954 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (82nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2016-9954?

CVE-2016-9954 affects Irregex Project Irregex. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2016-9954?

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-2016-9954 published?

CVE-2016-9954 was published on 2017-04-21 and last updated on 2026-06-17.

CVE-2016-9954

CVE-2016-9954 is a high-severity vulnerability in Irregex Project Irregex with a CVSS 3.x base score of 7.5. 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-399.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 5.0
EPSS exploit prediction: 2% (82nd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-399
Affected product: Irregex Project Irregex
Published: 2017-04-21
Last modified: 2026-06-17

Description

The backtrack compilation code in the Irregex package (aka IrRegular Expressions) before 0.9.6 for Scheme allows remote attackers to cause a denial of service (memory consumption) via a crafted regular expression with a repeating pattern.

Frequently asked questions

What is CVE-2016-9954?: The backtrack compilation code in the Irregex package (aka IrRegular Expressions) before 0.9.6 for Scheme allows remote attackers to cause a denial of service (memory consumption) via a crafted regular expression with a repeating pattern.
How severe is CVE-2016-9954?: CVE-2016-9954 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2016-9954 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (82nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2016-9954?: CVE-2016-9954 affects Irregex Project Irregex. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2016-9954?: 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-2016-9954 published?: CVE-2016-9954 was published on 2017-04-21 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:irregex_project:irregex:*:*:*:*:*:*:*:*

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