Security readout for executives and security teams
Plain-English summary
CVE-2021-28510 can disrupt Precision Time Protocol service on certain Arista EOS systems. A malformed PTP management or signaling packet can restart the PTP agent, and repeated packets can make the service unavailable. The reported impact is availability only, not data theft or device takeover.
Executive priority
Treat this as a moderate operational availability issue. Prioritize remediation where Arista switches support trading, telecom, industrial, logging, authentication, or other systems that rely on accurate time synchronization.
Technical view
The vulnerability is a CWE-400 resource management issue in Arista EOS PTP handling. An unauthenticated network packet with an invalid TLV in a PTP management/signaling message can trigger PTP agent restarts. CVSS 3.1 is 5.3: network reachable, low complexity, no privileges, no user interaction, low availability impact.
Likely exposure
Exposure is most relevant to organizations running affected Arista EOS releases on systems where PTP is enabled and reachable. The bundle lists EOS 4.22, 4.23.10, 4.24.8, 4.25.6, 4.26.4, and 4.27.1, but does not describe all platform or configuration conditions.
Exploitation context
The CVE is not listed as CISA KEV in the provided bundle, and no cited source here states active exploitation. The issue is network reachable and unauthenticated, but impact is limited to PTP service availability rather than full device compromise.
Researcher notes
The bundle does not include exploit proof, packet details, fixed-version specifics, or a complete affected-platform matrix. Validation should focus on version exposure, PTP enablement, reachability, logs, and Arista advisory details rather than attempting packet reproduction.
Mitigation direction
- Review Arista advisory 0076 for affected platforms and vendor-recommended fixed EOS releases.
- Upgrade affected EOS systems according to Arista guidance and operational change controls.
- Restrict PTP traffic to trusted clock peers and required network segments.
- Block untrusted paths to PTP services where operationally safe.
- Monitor PTP agent restarts and time synchronization health until remediation.
Validation and detection
- Inventory Arista EOS versions against the affected versions listed in the CVE bundle.
- Confirm whether PTP is enabled on potentially affected systems.
- Check whether untrusted networks can reach PTP management or signaling traffic.
- Review device logs for repeated PTP agent restarts or time synchronization loss.
- Map business services that depend on precise time from affected devices.
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-400: Exact CWE lookup
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Open ATT&CK lookupCVE-2021-28510 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
- 5.3 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
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:L/PR:N/UI:N/S:U/C:N/I:N/A:L3.91.4Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
5.3MediumVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Source materials
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.
Uncontrolled Resource Consumption
Uncontrolled Resource Consumption represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.