CVE-2026-88359
libfyaml 0.9.6 contains a stack exhaustion vulnerability in fy_atom_iter_format(). When...
libfyaml 0.9.6 contains a stack exhaustion vulnerability in fy_atom_iter_format(). When processing a specially crafted YAML document containing a very large literal or folded block scalar, the function repeatedly grows an internal buffer using alloca() inside a loop. The allocated stack memory is not released until the function returns, causing cumulative stack growth that can exceed the process stack limit and result in SIGSEGV and denial of service.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- Required
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used 6.5
libfyaml 0.9.6 contains a stack exhaustion vulnerability in fy_atom_iter_format(). When processing a specially crafted YAML document containing a very large literal or folded block scalar, the function repeatedly grows an internal buffer using alloca() inside a loop. The allocated stack memory is not released until the function returns, causing cumulative stack growth that can exceed the process stack limit and result in SIGSEGV and denial of service.
- Record
CVE-2026-88359- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H - Weakness
- CWE-770
- Updated
- 2026-11-02
EUVDEUVD-2026-85909 6.5
libfyaml 0.9.6 contains a stack exhaustion vulnerability in fy_atom_iter_format(). When processing a specially crafted YAML document containing a very large literal or folded block scalar, the function repeatedly grows an internal buffer using alloca() inside a loop. The allocated stack memory is not released until the function returns, causing cumulative stack growth that can exceed the process stack limit and result in SIGSEGV and denial of service.
- Record
EUVD-2026-85909- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-3qj9-89fg-m5cw 6.5
libfyaml 0.9.6 contains a stack exhaustion vulnerability in fy_atom_iter_format(). When...
libfyaml 0.9.6 contains a stack exhaustion vulnerability in fy_atom_iter_format(). When processing a specially crafted YAML document containing a very large literal or folded block scalar, the function repeatedly grows an internal buffer using alloca() inside a loop. The allocated stack memory is not released until the function returns, causing cumulative stack growth that can exceed the process stack limit and result in SIGSEGV and denial of service.
- Record
GHSA-3qj9-89fg-m5cw- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H - Weakness
- CWE-770
- Updated
- 2026-11-02
NVD 6.5
libfyaml 0.9.6 contains a stack exhaustion vulnerability in fy_atom_iter_format(). When processing a specially crafted YAML document containing a very large literal or folded block scalar, the function repeatedly grows an internal buffer using alloca() inside a loop. The allocated stack memory is not released until the function returns, causing cumulative stack growth that can exceed the process stack limit and result in SIGSEGV and denial of service.
- Record
CVE-2026-88359- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H - Weakness
- CWE-770
- Updated
- 2026-11-02
OSV 6.5
libfyaml 0.9.6 contains a stack exhaustion vulnerability in fy_atom_iter_format(). When processing a specially crafted YAML document containing a very large literal or folded block scalar, the function repeatedly grows an internal buffer using alloca() inside a loop. The allocated stack memory is not released until the function returns, causing cumulative stack growth that can exceed the process stack limit and result in SIGSEGV and denial of service.
- Record
CVE-2026-88359- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
OSVDEBIAN-CVE-2026-88359 6.5
libfyaml 0.9.6 contains a stack exhaustion vulnerability in fy_atom_iter_format(). When processing a specially crafted YAML document containing a very large literal or folded block scalar, the function repeatedly grows an internal buffer using alloca() inside a loop. The allocated stack memory is not released until the function returns, causing cumulative stack growth that can exceed the process stack limit and result in SIGSEGV and denial of service.
- Record
DEBIAN-CVE-2026-88359- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
OSVUBUNTU-CVE-2026-88359 6.5
libfyaml 0.9.6 contains a stack exhaustion vulnerability in fy_atom_iter_format(). When processing a specially crafted YAML document containing a very large literal or folded block scalar, the function repeatedly grows an internal buffer using alloca() inside a loop. The allocated stack memory is not released until the function returns, causing cumulative stack growth that can exceed the process stack limit and result in SIGSEGV and denial of service.
- Record
UBUNTU-CVE-2026-88359- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
Affected packages
| Package | Affected | Fixed |
|---|---|---|
libfyamlDebian:12 | All versions, plus listed versions 0.7.12-20.8-10.9-10.9-20.9.2-10.9.3-10.9.4-1 | None known |
libfyamlDebian:13 | All versions, plus listed versions 0.8-10.9-10.9-20.9.2-10.9.3-10.9.4-1 | None known |
libfyamlDebian:14 | All versions, plus listed versions 0.8-10.9-10.9-20.9.2-10.9.3-10.9.4-1 | None known |
libfyamlUbuntu:22.04:LTS | All versions, plus listed versions 0.7.11-20.7.12-1 | None known |
libfyamlUbuntu:24.04:LTS | All versions, plus listed versions 0.8-10.8-1build1 | None known |
libfyamlUbuntu:26.10 | All versions, plus listed versions 0.9.4-1 | None known |
libfyamlUbuntu:26.04:LTS | All versions, plus listed versions 0.8-1build10.9-20.9.2-10.9.3-10.9.4-1 | None known |
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-88359 is a medium vulnerability (CVSS 6.5) in libfyaml, published September 24, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.30%, the 22nd percentile. No source names a fixed version.
References
github.com/pantoniou/libfyaml/issues/315
github.com/pantoniou/libfyaml/commit/93741a7c9331da9da65ef7a25f2d7d6a817a1c29
github.com/pantoniou/libfyaml/commit/20502068902d58c076da873117985798df2c7e74
nvd.nist.gov/vuln/detail/CVE-2026-88359
github.com/advisories/GHSA-3qj9-89fg-m5cw
github.com/CVEProject/cvelistV5/tree/main/cves/2026/88xxx/CVE-2026-88359.json
security-tracker.debian.org/tracker/CVE-2026-88359
ubuntu.com/security/CVE-2026-88359
cve.org/CVERecord?id=CVE-2026-88359