Security readout for executives and security teams
Plain-English summary
CVE-2021-46853 is an availability issue in Alpine before 2.25. A remote condition involving LIST or LSUB before STARTTLS can crash the application. The business impact is service disruption for affected Alpine users, not known data theft or system takeover based on the supplied sources.
Executive priority
Handle through normal vulnerability management with moderate urgency. The main risk is application crash and disruption, not confirmed compromise. Prioritize if Alpine is used in business-critical mail workflows or managed workstation images.
Technical view
The CVE describes Alpine before 2.25 crashing when LIST or LSUB is sent before STARTTLS. CVSS 3.1 is 5.9, network reachable, no privileges or user interaction, high attack complexity, unchanged scope, and high availability impact only. The bundle maps it to CWE-367.
Likely exposure
Exposure is limited to environments running Alpine versions before 2.25. The bundle does not provide specific CPEs or a full affected-product matrix, so asset owners should confirm installed package versions through inventory and vendor advisories.
Exploitation context
The source bundle does not show CISA KEV listing or active exploitation evidence. Treat this as a denial-of-service risk where exploitation evidence is incomplete, not as a confirmed actively exploited vulnerability.
Researcher notes
Evidence is concise and product metadata is incomplete in the bundle. The key technical condition is LIST or LSUB before STARTTLS causing an Alpine crash before 2.25. Avoid assuming broader STARTTLS exposure beyond the cited CVE and references.
Mitigation direction
- Upgrade Alpine to version 2.25 or later where available.
- Review Gentoo GLSA-202301-07 for distribution-specific package guidance.
- Check vendor or distribution advisories for supported fixed builds.
- Prioritize remediation on systems where Alpine use is operationally important.
Validation and detection
- Inventory systems for Alpine versions earlier than 2.25.
- Confirm package status against Gentoo advisory or your distribution tracker.
- Validate that upgraded systems report Alpine 2.25 or later.
- Document any unsupported legacy installations and compensating controls.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-367: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2021-46853 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Medium
- CVSS
- 5.9 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H2.23.6Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
5.9MediumVector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://nostarttls.secvuln.info/CVE reference
- https://bugs.gentoo.org/807613CVE reference
- GLSA-202301-07CVE reference · vendor-advisory
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Time-of-check Time-of-use (TOCTOU) Race Condition
Time-of-check Time-of-use (TOCTOU) Race Condition represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.