Security readout for executives and security teams
Plain-English summary
Hermes WebUI before 0.51.307 can be tricked into treating a remote attacker as local by spoofing an X-Forwarded-For loopback address. That can bypass onboarding protections and may let an attacker change AI provider settings, steal or replace credentials, or reach internal services such as cloud metadata endpoints.
Executive priority
Treat this as urgent for any exposed Hermes WebUI instance. Patch first, then verify proxy header handling and credential integrity, because the reported impacts include credential compromise and internal service access.
Technical view
The flaw is an authentication bypass in local-origin IP checks for onboarding endpoints. Client-controlled X-Forwarded-For values can satisfy loopback restrictions. Reported impact includes SSRF to internal services, attacker-controlled LLM provider configuration and API keys, and OAuth device-code flows producing persistent tokens in auth.json.
Likely exposure
Highest exposure is Hermes WebUI deployments before 0.51.307 reachable from untrusted networks, especially behind proxies that pass client-supplied X-Forwarded-For headers or in cloud environments with metadata services.
Exploitation context
The bundle does not show CISA KEV listing or active exploitation evidence. Exploitation is described as unauthenticated, remote, low-complexity, and not requiring user interaction, which makes exposed instances urgent to assess.
Researcher notes
Evidence points to CWE-348 style trust in an unverified forwarding header. Assess the patched version, PR, and commit for exact guard changes, and avoid assuming broader affected products beyond nesquena/hermes-webui.
Mitigation direction
- Upgrade Hermes WebUI to 0.51.307 or later.
- Restrict WebUI and onboarding endpoints to trusted networks.
- Strip or overwrite client-supplied X-Forwarded-For at trusted proxies.
- Rotate LLM provider keys and OAuth tokens if compromise is suspected.
- Review vendor guidance for any additional hardening steps.
Validation and detection
- Inventory Hermes WebUI instances and confirm installed versions.
- Identify internet-facing or broadly reachable deployments.
- Review proxy handling of X-Forwarded-For and trusted proxy settings.
- Check auth.json, provider settings, and API keys for unauthorized changes.
- Review logs for unexpected onboarding, OAuth, or internal-service access.
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-348: 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 lookupCredential and access behavior lookup
The CVE wording references authentication or credential exposure, so valid-account and credential-access review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCloud metadata behavior lookup
The CVE wording references SSRF or metadata access, so cloud discovery and credential material review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2026-58122 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
- Critical
- CVSS
- 9.3 (4.0)
- Known Exploited
- No
- Published
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA: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.
SSVC decision data
CVSS vector scores
2 official scoresWe 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:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N——VulnCheckCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N3.95.2VulnCheckVulnerability scoring details
Base CVSS 4.0 score
9.3CriticalVector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
Base CVSS 3.1 score
9.1CriticalVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- CVE publishedCVE Program
The CVE record was published.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
Source materials
- CVE List V5 sourceCVE List V5
- Release NotesCVE reference, VulnCheck · release-notes
- Pull RequestCVE reference, VulnCheck · issue-tracking
- Patch CommitCVE reference, VulnCheck · patch
- https://www.vulncheck.com/advisories/hermes-webui-authentication-bypass-via-x-forwarded-for-header-spoofingCVE reference, VulnCheck · third-party-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.
Use of Less Trusted Source
Use of Less Trusted Source represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.