How severe is CVE-2019-19203?

CVE-2019-19203 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-2019-19203 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-2019-19203?

CVE-2019-19203 primarily affects Oniguruma Project Oniguruma. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2019-19203?

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-2019-19203 published?

CVE-2019-19203 was published on 2019-11-21 and last updated on 2026-06-17.

CVE-2019-19203

CVE-2019-19203 is a high-severity vulnerability in Oniguruma Project Oniguruma 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-125.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 5.0
EPSS exploit prediction: 4% (89th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-125
Affected product: Oniguruma Project Oniguruma
Published: 2019-11-21
Last modified: 2026-06-17

Description

An issue was discovered in Oniguruma 6.x before 6.9.4_rc2. In the function gb18030_mbc_enc_len in file gb18030.c, a UChar pointer is dereferenced without checking if it passed the end of the matched string. This leads to a heap-based buffer over-read.

Frequently asked questions

What is CVE-2019-19203?: An issue was discovered in Oniguruma 6.x before 6.9.4_rc2. In the function gb18030_mbc_enc_len in file gb18030.c, a UChar pointer is dereferenced without checking if it passed the end of the matched string. This leads to a heap-based buffer over-read.
How severe is CVE-2019-19203?: CVE-2019-19203 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-2019-19203 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-2019-19203?: CVE-2019-19203 primarily affects Oniguruma Project Oniguruma. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2019-19203?: 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-2019-19203 published?: CVE-2019-19203 was published on 2019-11-21 and last updated on 2026-06-17.

References

Affected products (4)

cpe:2.3:a:oniguruma_project:oniguruma:*:*:*:*:*:*:*:*
cpe:2.3:a:oniguruma_project:oniguruma:6.9.4:rc1:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:30:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:31:*:*:*:*:*:*:*

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