CVE-2017-9226

Severity: critical (CVSS 9.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 7.5% 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 or read occurs in next_state_val() during regular expression compilation. Octal numbers larger than 0xff are not handled correctly in fetch_token() and fetch_token_in_cc(). A malformed regular expression containing an octal number in the form of '\700' would produce an invalid code point value larger than 0xff in next_state_val(), resulting in an out-of-bounds write memory corruption.

Affected products

Oniguruma Project Oniguruma: 6.2.0
PHP: 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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