CVE-2017-9228

Severity: critical (CVSS 9.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 6.3% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2017-05-24 · updated 2026-06-17
Weakness: CWE-787

Description

An issue was discovered in Oniguruma 6.2.0, as used in Oniguruma-mod in Ruby through 2.4.1 and mbstring in PHP through 7.1.5. A heap out-of-bounds write occurs in bitset_set_range() during regular expression compilation due to an uninitialized variable from an incorrect state transition. An incorrect state transition in parse_char_class() could create an execution path that leaves a critical local variable uninitialized until it's used as an index, resulting in an out-of-bounds write memory corruption.

Affected products

Oniguruma Project Oniguruma: 6.2.0
PHP: from 5.6.0 before 5.6.31; from 7.0.0 before 7.0.21; from 7.1.0 before 7.1.7 — fixed in 5.6.31, 7.0.21, 7.1.7

How to fix

Upgrade to a fixed version: PHP 5.6.31, 7.0.21, 7.1.7. Check the vendor advisory for mitigations.

References

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