Security readout for executives and security teams
Plain-English summary
CVE-2021-29622 is an open redirect in Prometheus. A crafted URL under the /new endpoint can send a user from a trusted Prometheus server to an attacker-chosen site. This does not directly compromise the server, but it can support phishing or credential-harvesting campaigns that abuse trust in monitoring infrastructure.
Executive priority
Treat this as a moderate-priority remediation for internet-facing or broadly accessible Prometheus servers. It is not a server takeover issue, but it can undermine trust in monitoring portals and assist phishing. Patch during the next normal security maintenance window unless public exposure is confirmed.
Technical view
Prometheus 2.23.0 introduced redirects from /new to / for the new UI transition. A bug allowed arbitrary external redirects through that endpoint. The issue is CWE-601, network reachable, low complexity, unauthenticated, and requires user interaction. Sources report fixes in 2.26.1 and 2.27.1, with /new removed in 2.28.0.
Likely exposure
Exposure is likely where Prometheus versions from 2.23.0 through affected pre-fix releases expose /new to users or the internet. Risk is lower if Prometheus is not user-accessible, is tightly reverse-proxied, or already runs a fixed release.
Exploitation context
The bundle does not cite active exploitation, and KEV status is false. Exploitation requires a user to visit a crafted Prometheus URL. The main impact is redirecting that user to an arbitrary site, not code execution or data theft from Prometheus itself.
Researcher notes
Focus validation on version, endpoint reachability, and proxy behavior. Do not assume broader Prometheus compromise from this CVE. The source bundle names arbitrary redirect behavior only and provides no evidence of active exploitation or additional affected products.
Mitigation direction
- Upgrade Prometheus to 2.26.1, 2.27.1, or a later fixed release.
- Move to 2.28.0 or later where /new is removed, if compatible.
- Block access to /new at a reverse proxy as the documented workaround.
- Review vendor release notes before applying operational changes.
Validation and detection
- Inventory Prometheus instances and record exact running versions.
- Confirm whether /new is reachable through public or internal entry points.
- Verify reverse proxy rules block /new if upgrade is delayed.
- Confirm deployed versions match fixed release guidance.
- Review user-facing Prometheus links for exposure to crafted redirects.
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-601: User-session and phishing behavior lookup
Client-side and session-facing weaknesses should be reviewed alongside initial-access and user-execution behaviors. 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 lookupDatabase behavior lookup
The CVE wording references database injection or access, so collection and exfiltration review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2021-29622 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
- 6.5 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
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:R/S:U/C:N/I:H/A:N2.83.6Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
6.5MediumVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/prometheus/prometheus/security/advisories/GHSA-vx57-7f4q-fpc7CVE reference · x_refsource_CONFIRM
- https://github.com/prometheus/prometheus/releases/tag/v2.26.1CVE reference · x_refsource_MISC
- https://github.com/prometheus/prometheus/releases/tag/v2.27.1CVE reference · x_refsource_MISC
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.
URL Redirection to Untrusted Site ('Open Redirect')
URL Redirection to Untrusted Site ('Open Redirect') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.