CVE-2026-55558

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

0.40% probability of exploitation activity in the next 30 days.

EPSS percentile

Equal to or higher than the score of 34.2% of scored records. A rank, not a probability.

NVD base score

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

NVD CVSS vector

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

NVD analysis status

Deferred. 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 14:29Z2 MO AGO

Last updated

2026-08-20 20:00Z2 MO AGO

Reserved

2026-06-16

Assigning CNA

GitHub_M

Record state

PUBLISHED

Severity

Medium (CVSS 5.9)

CNA CVSS vector

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

Weaknesses

• CWE-74Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')Class

Data version

5.2

Document digest

17e7e6954896154c465fa46431c6803227e32643c8dc42fa455b0c554baf3b4e

• github.comhttps://github.com/cole/aiosmtplib/security/advisories/GHSA-vxj7-4xrp-5vr4x_refsource_CONFIRM
• github.comhttps://github.com/cole/aiosmtplib/commit/9fab7ba1361dbf7622ede1315a24be805cff09c9x_refsource_MISC
• github.comhttps://github.com/cole/aiosmtplib/releases/tag/v5.1.2x_refsource_MISC