CVE-2017-9226 — An issue was discovered in Oniguruma 6

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 correc

01What is this vulnerability?

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…

02Affected products

No structured affected-product list available — see references below for vendor advisories.

03Active exploitation status

Not currently listed on the CISA Known Exploited Vulnerabilities (KEV) catalog. EPSS is the best forward-looking signal — see the EPSS row above.

04Recommended remediation

• Patch to a fixed version listed in the vendor advisory (see references below).
• Mitigate with WAF rules, network egress filters, or feature flags where the patch is not yet available.
• Hunt historical logs for exploitation indicators — see Detection signatures below.

05Technical details

For the full vendor write-up, exploit chains, and reference implementations, see the references list in section 09.

06Detection signatures

Ask SARA in chat to draft a starting detection for this CVE in your stack of choice.

07Related CVEs

No directly-cited follow-up CVEs in the KB record for this advisory. The references list in section 09 carries the vendor cross-references.

08Timeline

• Published: 2017-05-24T15:29:00.277
• Last modified: 2026-05-13T00:24:29.033

09References

• www.securityfocus.com — http://www.securityfocus.com/bid/101244
• access.redhat.com — https://access.redhat.com/errata/RHSA-2018:1296
• github.com — https://github.com/kkos/oniguruma/commit/b4bf968ad52afe14e60a2dc8a95d3555c543353…
• github.com — https://github.com/kkos/oniguruma/commit/f015fbdd95f76438cd86366467bb2b39870dd7c…
• github.com — https://github.com/kkos/oniguruma/issues/55
• www.securityfocus.com — http://www.securityfocus.com/bid/101244
• access.redhat.com — https://access.redhat.com/errata/RHSA-2018:1296
• github.com — https://github.com/kkos/oniguruma/commit/b4bf968ad52afe14e60a2dc8a95d3555c543353…
• github.com — https://github.com/kkos/oniguruma/commit/f015fbdd95f76438cd86366467bb2b39870dd7c…
• github.com — https://github.com/kkos/oniguruma/issues/55