CVE-2026-56389

Exploitation

Assessed, none found. CISA's assessment recorded neither public exploit code nor evidence of exploitation when it was made.

SSVC decision

• ExploitationnoneCISA recorded no public exploit code and no evidence of exploitation.
• AutomatablenoAt least one step from reconnaissance to exploitation cannot be reliably automated.
• Technical ImpactpartialSuccessful exploitation gives limited control of the vulnerable component.

CISA publishes the decision points, not a final SSVC decision. The decision also depends on mission and well-being impact, which is a property of your deployment rather than of the vulnerability.

EPSS probability

0.22% probability of exploitation activity in the next 30 days.

EPSS percentile

Equal to or higher than the score of 12.8% of scored records. A rank, not a probability.

NVD base score

6.8 (CVSS v4.0), scored by the NVD independently of the CNA.

NVD CVSS vector

CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:H/VA:L/SC:L/SI:L/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

NVD analysis status

Analyzed. NVD last modified this record on 2026-10-23.

Red Hat severity

Moderate. Red Hat's rating for its own products, not a CVSS rating.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

Published

2026-07-29 09:39Z3 MO AGO

Last updated

2026-07-29 12:21Z3 MO AGO

Reserved

2026-06-21

Assigning CNA

CERT-PL

Record state

PUBLISHED

Severity

Medium (CVSS 6.8)

CNA CVSS vector

CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:H/VA:L/SC:L/SI:L/SA:L

Weaknesses

• CWE-78Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')Base

Data version

5.2

Document digest

9f508077b109df187dcc732875c9f8cd3d4760f63af631f815754f92f498b6c7

• cert.plhttps://cert.pl/en/posts/2026/07/CVE-2026-56389third-party-advisory
• cgit.git.savannah.gnu.orghttps://cgit.git.savannah.gnu.org/cgit/bison.git/product
• cgit.git.savannah.gnu.orghttps://cgit.git.savannah.gnu.org/cgit/bison.git/commit/?id=3169c1e7a2c6acc4c59dfcf8b089896d6881925bpatch