CVE-2026-77639

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.
• AutomatableyesAn attacker can reliably automate reconnaissance through exploitation, so this scales.
• 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

0.39% probability of exploitation activity in the next 30 days.

EPSS percentile

Equal to or higher than the score of 32.9% of scored records. A rank, not a probability.

NVD base score

5.3 (CVSS v3.x), scored by the NVD independently of the CNA.

NVD CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

NVD analysis status

Analyzed. NVD last modified this record on 2026-10-18.

Red Hat severity

No Red Hat rating. Red Hat rates the CVEs that affect its products.

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

2026-08-20 20:57Z2 MO AGO

Last updated

2026-08-21 20:08Z2 MO AGO

Reserved

2026-08-20

Assigning CNA

mitre

Record state

PUBLISHED

Severity

Medium (CVSS 5.3)

CNA CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Weaknesses

• CWE-420Unprotected Alternate ChannelBase

Data version

5.2

Document digest

3c3283bab587466dc1853774dd0b12b20cdc003fe88a2faeaae129dbe0c28c7c

• gitlab.torproject.orghttps://gitlab.torproject.org/tpo/core/tor/-/raw/tor-0.4.9.9/ChangeLog