Security readout for executives and security teams
Plain-English summary
This flaw is in Oniguruma regular-expression handling, used by older Ruby and PHP mbstring builds. A malformed regular expression can cause a stack buffer overwrite while the expression is compiled. Business risk depends on whether applications let users influence regex patterns or run old runtimes.
Executive priority
Prioritize remediation for internet-facing or multi-tenant applications that accept custom regex patterns and run old Ruby, PHP, or Oniguruma components. Treat legacy runtime retirement as the durable fix path.
Technical view
In Oniguruma 6.2.0, unicode_unfold_key() mishandles code point 0xFFFFFFFF, leading onigenc_unicode_get_case_fold_codes_by_str() to write four bytes past a stack buffer in expand_case_fold_string() during regex compilation.
Likely exposure
Systems are most likely exposed if they use Oniguruma 6.2.0 directly, Ruby through 2.4.1 with Oniguruma-mod, or PHP through 7.1.5 mbstring. Exposure is higher where untrusted users can supply or influence regular expressions.
Exploitation context
The sources describe a malformed regular expression triggering stack out-of-bounds write during compilation. The bundle does not cite active exploitation, weaponized public exploit use, CVSS, or CISA KEV listing.
Researcher notes
The CVE record gives precise vulnerable code paths and affected version ranges but lacks CVSS, CWE, named fixed releases, and exploitation evidence. The GitHub commit and issue are the key technical references for patch verification.
Mitigation direction
- Inventory Ruby, PHP mbstring, and direct Oniguruma use.
- Update affected runtimes or libraries using vendor guidance.
- Verify whether builds include Oniguruma commit 166a6c3999bf06b4de0ab4ce6b088a468cc4029f.
- Avoid compiling user-controlled regular expressions where feasible.
- Add input controls around features accepting custom regex patterns.
Validation and detection
- Check deployed Ruby versions are not through 2.4.1.
- Check deployed PHP mbstring versions are not through 7.1.5.
- Identify direct Oniguruma 6.2.0 dependencies in application builds.
- Review application features that accept user-supplied regex patterns.
- Confirm patched source or package provenance against vendor records.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CVE-2017-9225 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Unknown
- CVSS
- Not scored
- Known Exploited
- No
- Published
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS and timeline data
No CVSS vectors or timeline events were available in the normalized CVE source material.
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/kkos/oniguruma/commit/166a6c3999bf06b4de0ab4ce6b088a468cc4029fCVE reference · x_refsource_CONFIRM
- https://github.com/kkos/oniguruma/issues/56CVE reference · x_refsource_CONFIRM
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.