What’s Vulnerable › Vulnerabilities

CVE-2017-9225

• Severity: critical (CVSS 9.8 v3.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 3.1% 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 stack out-of-bounds write in onigenc_unicode_get_case_fold_codes_by_str() occurs during regular expression compilation. Code point 0xFFFFFFFF is not properly handled in unicode_unfold_key(). A malformed regular expression could result in 4 bytes being written off the end of a stack buffer of expand_case_fold_string() during the call to onigenc_unicode_get_case_fold_codes_by_str(), a typical stack buffer overflow.

Affected products

• Oniguruma Project Oniguruma: 6.2.0
• PHP: through 7.1.5
• Ruby: through 2.4.1

References

• https://github.com/kkos/oniguruma/commit/166a6c3999bf06b4de0ab4ce6b088a468cc4029f
• https://github.com/kkos/oniguruma/issues/56
• https://github.com/kkos/oniguruma/commit/166a6c3999bf06b4de0ab4ce6b088a468cc4029f
• https://github.com/kkos/oniguruma/issues/56

Get alerted when CVE-2017-9225 or the next vulnerability affects your stack