When a file is processed, an infinite loop occurs in next_inline() of the more_curly() function.
Priority LOW 24CWE-835Published · Updated
Key facts
- Attack vector
- Local
- Privileges required
- None
- User interaction
- Required
- Attack complexity
- Low
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Deferred Red Hat: fix deferred
Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA and Red Hat. Impact type from CWE-835.
Summary
When a file is processed, an infinite loop occurs in next_inline() of the more_curly() function.
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00227 13th percentileScored 2026-11-07
Fix Deferred Red Hat: fix deferred
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| — | byacc | <1.9.20200330 and <2.0.20210808 | — | No fix listed | CNA |
- byacc Vendor— Affected <1.9.20200330 and <2.0.20210808 Fixed in — No fix listed CNA
Remediation
No fixed version listed by the sources yet.
Vendor assessments
Red Hat
Red Hat rating: Low. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 6 | Affected | No fix planned: Out of support scope |
| Red Hat Enterprise Linux 7 | Affected | No fix yet: Fix deferred |
Not affected: 2 products
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
Timeline
- 2026-10-02 Threatist record created from CVE-2021-33642
- 2026-10-03 Alias added: GHSA-q8mx-78gm-98mh
References
More openEuler Byacc vulnerabilities
- TI-2021-13015 Use after free in byacc CVSS 3.1HIGH 7.8
Sources
- CVE-2021-33642 · CVE Program
- CVE-2021-33642 · NVD
- FIRST EPSS
- GHSA-q8mx-78gm-98mh · GitHub Advisory Database · CC BY 4.0
- CVE-2021-33642 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences