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.
Conclusion & alert: CVE-2017-9225 is rated High Exploit Risk (69.8/100): CVSS Critical severity, with low exploitation likelihood (EPSS 0.22%). Core evidence: 1 public exploit reference(s) are indexed (Exploit-DB). Mandatory action: Public exploits are available—assess exposure, apply mitigations, and prioritize patching.
Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.
| EDB-ID | Source | Kind | Published | Link |
|---|---|---|---|---|
| — | nvd_ref | exploit_tag | Exploit-DB ↗ |
EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).
| # | Date | Old EPSS score | New EPSS score | Delta (New - Old) |
|---|---|---|---|---|
| 1 | 2026-05-14 | 0.29% | 0.22% | -0.07% |
| 2 | 2026-01-14 | 0.43% | 0.29% | -0.14% |
| 3 | 2025-03-30 | — | 0.43% | — |
Full EPSS history (12 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 9.8 | 3.0 | CRITICAL |
|
3.9 | 5.9 | [email protected] |
| 7.5 | 2.0 | HIGH |
|
10.0 | 6.4 | [email protected] |
| vendor | priority | summary | link |
|---|---|---|---|
debian
|
not yet assigned | CVE-2017-9225 not yet assigned priority: Debian including 1 source packages (libonig), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. | https://security-tracker.debian.org/tracker/CVE-2017-9225 |
redhat
|
medium | — | https://access.redhat.com/security/cve/CVE-2017-9225 |
suse
|
medium | CVE-2017-9225 severity moderate: SUSE including 171 source package names (apache2-mod_php5, apache2-mod_php53, …), 216 product×package rows across 16 product lines (Magnum Orchestration 7, SUSE Lifecycle Management Server 1.3, … (16 product lines)): Known Not Affected 216. | https://www.suse.com/security/cve/CVE-2017-9225/ |
ubuntu
|
medium | CVE-2017-9225 medium priority: Ubuntu including 4 source packages (libonig, php5, php7.0, php7.1), 25 status rows across 7 suites (artful, bionic, trusty, upstream, xenial, yakkety, zesty): DNE 11, not-affected 8, needs-triage 4, ignored 2. | https://ubuntu.com/security/CVE-2017-9225 |
| URL | Tags |
|---|---|
| https://github.com/kkos/oniguruma/commit/166a6c3999bf06b4de0ab4ce6b088a468cc4029f | Patch Third Party Advisory |
| https://github.com/kkos/oniguruma/issues/56 | Exploit Third Party Advisory |