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CVE-2026-53523

Nezha Monitoring: OAuth2 Redirect URL — Host Header Injection

6.8 MediumFix available

Nezha Monitoring is a self-hostable, lightweight, servers and websites monitoring and O&M tool. From version 1.0.0 to before version 2.2.0, the getRedirectURL function in oauth2.go:22-29 constructs the OAuth2 callback URL by concatenating the request's Host header with a fixed path, with zero validation of the Host header. This can result in host header injection. This issue has been patched in version 2.2.0.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
High
Privileges needed
None
User interaction
Required

What an attacker can affect

Confidentiality
High
Integrity
High
Availability
None

Exploit likelihood

0.29%Up 0.3 points since Jun 13, 2026
90%50%10%1%

What each source reports

CVE List Score used 6.8

Nezha Monitoring: OAuth2 Redirect URL — Host Header Injection

Nezha Monitoring is a self-hostable, lightweight, servers and websites monitoring and O&M tool. From version 1.0.0 to before version 2.2.0, the getRedirectURL function in oauth2.go:22-29 constructs the OAuth2 callback URL by concatenating the request's Host header with a fixed path, with zero validation of the Host header. This can result in host header injection. This issue has been patched in version 2.2.0.

Record
CVE-2026-53523
CVSS 3.1
6.8 MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N
Weakness
CWE-601
Updated
2026-11-02
EUVDEUVD-2026-36602 6.8

Nezha Monitoring is a self-hostable, lightweight, servers and websites monitoring and O&M tool. From version 1.0.0 to before version 2.2.0, the getRedirectURL function in oauth2.go:22-29 constructs the OAuth2 callback URL by concatenating the request's Host header with a fixed path, with zero validation of the Host header. This can result in host header injection. This issue has been patched in version 2.2.0.

Record
EUVD-2026-36602
CVSS 3.1
6.8 MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N
Updated
2026-11-02
GitHub AdvisoriesGHSA-9rc6-8cjv-rcvx 6.8

Nezha Monitoring: OAuth2 Redirect URL — Host Header Injection

1. Description

The getRedirectURL function in oauth2.go:22-29 constructs the OAuth2 callback URL by concatenating the request's Host header with a fixed path, with zero validation of the Host header:

func getRedirectURL(c *gin.Context) string {
    scheme := "http://"
    referer := c.Request.Referer()
    if forwardedProto := c.Request.Header.Get("X-Forwarded-Proto"); forwardedProto == "https" || strings.HasPrefix(referer, "https://") {
        scheme = "https://"
    }
    return scheme + c.Request.Host + "/api/v1/oauth2/callback"
}

File: cmd/dashboard/controller/oauth2.go:22-29

This function is called from oauth2redirect() at line 53:

func oauth2redirect(c *gin.Context) (*model.Oauth2LoginResponse, error) {
    // ...
    redirectURL := getRedirectURL(c)
    o2conf := o2confRaw.Setup(redirectURL)
    // ...
    url := o2conf.AuthCodeURL(state, oauth2.AccessTypeOnline)
    return &model.Oauth2LoginResponse{Redirect: url}, nil
}

The redirectURL is passed into o2confRaw.Setup(redirectURL) which configures the OAuth2 Config.RedirectURL field (oauth2config.go:22-33). This RedirectURL is sent to the OAuth2 provider (e.g., GitHub, Google, Microsoft) as the callback endpoint. The OAuth2 provider will redirect the user's browser — along with the authorization code — to this URL after the user authenticates.

The security issue is that c.Request.Host is directly user-controllable via the HTTP Host header. An attacker who can control which Host header reaches the oauth2redirect handler can:

  1. Set Host: evil.com
  2. getRedirectURL returns https://evil.com/api/v1/oauth2/callback
  3. The OAuth2 provider redirects the victim's auth code to evil.com
  4. The attacker's server at evil.com captures the auth code
  5. The attacker exchanges the code for an access token, binding the victim's OAuth identity to the attacker's dashboard account

The scheme detection (lines 24-27) uses X-Forwarded-Proto and the Referer header, both of which are also user-controllable in certain configurations, so the attacker can force https:// scheme in the redirect URL.

The oauth2callback handler at line 129 later uses state.RedirectURL (which is stored in singleton.Cache at line 65) when calling exchangeOpenId at line 152. The cached redirectURL was set during the initial oauth2redirect call, tying the attack flow together.

2. PoC

A conceptual attack (no Docker needed):

Scenario: OAuth2 provider has loose redirect URI validation
          (e.g., allows wildcard subdomain matching)

1. Attacker crafts a URL to the dashboard's OAuth2 login endpoint
   with a modified Host header:

   GET /api/v1/oauth2/github HTTP/1.1
   Host: attacker-controlled.com
   X-Forwarded-Proto: https

2. The dashboard responds with a redirect to:
   https://github.com/login/oauth/authorize?client_id=...&redirect_uri=https://attacker-controlled.com/api/v1/oauth2/callback&state=...

3. Victim clicks the attacker's link → authenticates with GitHub
   → GitHub redirects to https://attacker-controlled.com/api/v1/oauth2/callback?code=AUTH_CODE&state=...

4. Attacker captures the AUTH_CODE from their server logs

5. Attacker exchanges the code at the real dashboard's
   /api/v1/oauth2/callback endpoint (using the real Host header
   this time), binding the victim's OAuth identity to their
   dashboard account

Prerequisites for full exploit:

  • The victim must click the attacker's crafted link
  • The OAuth2 provider must accept the attacker's domain as a valid redirect URI (some providers accept https://*/* or allow wildcards; others are strict)

3. Impact

  • Account takeover: an attacker who intercepts the OAuth2 authorization code can bind the victim's OAuth identity (GitHub, Google, GitLab, etc.) to their own dashboard account, gaining the victim's access level and permissions
  • Privilege escalation: if the victim is an admin, the attacker gains full administrative…
Record
GHSA-9rc6-8cjv-rcvx
CVSS 3.1
6.8 MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N
Weakness
CWE-601
Updated
2026-11-02
NVD 6.8

Nezha Monitoring is a self-hostable, lightweight, servers and websites monitoring and O&M tool. From version 1.0.0 to before version 2.2.0, the getRedirectURL function in oauth2.go:22-29 constructs the OAuth2 callback URL by concatenating the request's Host header with a fixed path, with zero validation of the Host header. This can result in host header injection. This issue has been patched in version 2.2.0.

Record
CVE-2026-53523
CVSS 3.1
6.8 MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N
Weakness
CWE-601
Updated
2026-11-02
OSV 6.8

Nezha Monitoring: OAuth2 Redirect URL — Host Header Injection

Nezha Monitoring is a self-hostable, lightweight, servers and websites monitoring and O&M tool. From version 1.0.0 to before version 2.2.0, the getRedirectURL function in oauth2.go:22-29 constructs the OAuth2 callback URL by concatenating the request's Host header with a fixed path, with zero validation of the Host header. This can result in host header injection. This issue has been patched in version 2.2.0.

Record
CVE-2026-53523
CVSS 3.1
6.8 MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N
Weakness
CWE-601
Updated
2026-11-02
OSVGHSA-9rc6-8cjv-rcvx 6.8

Nezha Monitoring: OAuth2 Redirect URL — Host Header Injection

1. Description

The getRedirectURL function in oauth2.go:22-29 constructs the OAuth2 callback URL by concatenating the request's Host header with a fixed path, with zero validation of the Host header:

func getRedirectURL(c *gin.Context) string {
    scheme := "http://"
    referer := c.Request.Referer()
    if forwardedProto := c.Request.Header.Get("X-Forwarded-Proto"); forwardedProto == "https" || strings.HasPrefix(referer, "https://") {
        scheme = "https://"
    }
    return scheme + c.Request.Host + "/api/v1/oauth2/callback"
}

File: cmd/dashboard/controller/oauth2.go:22-29

This function is called from oauth2redirect() at line 53:

func oauth2redirect(c *gin.Context) (*model.Oauth2LoginResponse, error) {
    // ...
    redirectURL := getRedirectURL(c)
    o2conf := o2confRaw.Setup(redirectURL)
    // ...
    url := o2conf.AuthCodeURL(state, oauth2.AccessTypeOnline)
    return &model.Oauth2LoginResponse{Redirect: url}, nil
}

The redirectURL is passed into o2confRaw.Setup(redirectURL) which configures the OAuth2 Config.RedirectURL field (oauth2config.go:22-33). This RedirectURL is sent to the OAuth2 provider (e.g., GitHub, Google, Microsoft) as the callback endpoint. The OAuth2 provider will redirect the user's browser — along with the authorization code — to this URL after the user authenticates.

The security issue is that c.Request.Host is directly user-controllable via the HTTP Host header. An attacker who can control which Host header reaches the oauth2redirect handler can:

  1. Set Host: evil.com
  2. getRedirectURL returns https://evil.com/api/v1/oauth2/callback
  3. The OAuth2 provider redirects the victim's auth code to evil.com
  4. The attacker's server at evil.com captures the auth code
  5. The attacker exchanges the code for an access token, binding the victim's OAuth identity to the attacker's dashboard account

The scheme detection (lines 24-27) uses X-Forwarded-Proto and the Referer header, both of which are also user-controllable in certain configurations, so the attacker can force https:// scheme in the redirect URL.

The oauth2callback handler at line 129 later uses state.RedirectURL (which is stored in singleton.Cache at line 65) when calling exchangeOpenId at line 152. The cached redirectURL was set during the initial oauth2redirect call, tying the attack flow together.

2. PoC

A conceptual attack (no Docker needed):

Scenario: OAuth2 provider has loose redirect URI validation
          (e.g., allows wildcard subdomain matching)

1. Attacker crafts a URL to the dashboard's OAuth2 login endpoint
   with a modified Host header:

   GET /api/v1/oauth2/github HTTP/1.1
   Host: attacker-controlled.com
   X-Forwarded-Proto: https

2. The dashboard responds with a redirect to:
   https://github.com/login/oauth/authorize?client_id=...&redirect_uri=https://attacker-controlled.com/api/v1/oauth2/callback&state=...

3. Victim clicks the attacker's link → authenticates with GitHub
   → GitHub redirects to https://attacker-controlled.com/api/v1/oauth2/callback?code=AUTH_CODE&state=...

4. Attacker captures the AUTH_CODE from their server logs

5. Attacker exchanges the code at the real dashboard's
   /api/v1/oauth2/callback endpoint (using the real Host header
   this time), binding the victim's OAuth identity to their
   dashboard account

Prerequisites for full exploit:

  • The victim must click the attacker's crafted link
  • The OAuth2 provider must accept the attacker's domain as a valid redirect URI (some providers accept https://*/* or allow wildcards; others are strict)

3. Impact

  • Account takeover: an attacker who intercepts the OAuth2 authorization code can bind the victim's OAuth identity (GitHub, Google, GitLab, etc.) to their own dashboard account, gaining the victim's access level and permissions
  • Privilege escalation: if the victim is an admin, the attacker gains full administrative…
Record
GHSA-9rc6-8cjv-rcvx
CVSS 3.1
6.8 MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N
Weakness
CWE-601
Updated
2026-11-02
OSVGO-2026-5829 No score

Nezha Monitoring: OAuth2 Redirect URL — Host Header Injection in github.com/nezhahq/nezha

Nezha Monitoring: OAuth2 Redirect URL — Host Header Injection in github.com/nezhahq/nezha.

NOTE: The source advisory for this report contains additional versions that could not be automatically mapped to standard Go module versions.

(If this is causing false-positive reports from vulnerability scanners, please suggest an edit to the report.)

The additional affected modules and versions are: github.com/nezhahq/nezha before v2.2.0.

Record
GO-2026-5829
Updated
2026-11-02
OSVopenSUSE-SU-2026:21483-1 No score

Security update for govulncheck-vulndb

This update for govulncheck-vulndb fixes the following issues:

  • Update to version 0.0.20260723T184607 2026-07-23T18:46:07Z (jsc#PED-11136).

Go CVE Numbering Authority IDs added or updated with aliases:

  • GO-2026-4730 CVE-2026-33022 GHSA-cv4x-93xx-wgfj
  • GO-2026-4761 CVE-2026-33211 GHSA-j5q5-j9gm-2w5c
  • GO-2026-5102 CVE-2026-45021 GHSA-3vcp-chfh-f6r2
  • GO-2026-5272 CVE-2026-40938 GHSA-94jr-7pqp-xhcq
  • GO-2026-5486 CVE-2026-40924 GHSA-m2cx-gpqf-qf74
  • GO-2026-5542 CVE-2026-40090 GHSA-pj97-4p9w-gx3q
  • GO-2026-5630 CVE-2026-25542 GHSA-rmx9-2pp3-xhcr
  • GO-2026-5643 CVE-2026-40923 GHSA-rx35-6rhx-7858
  • GO-2026-5675 CVE-2026-41492 GHSA-vvf7-6rmr-m29q
  • GO-2026-5711 CVE-2026-40161 GHSA-wjxp-xrpv-xpff
  • GO-2026-5746 CVE-2026-41567 GHSA-x86f-5xw2-fm2r
  • GO-2026-5749 CVE-2026-41328 GHSA-x92x-px7w-4gx4
  • GO-2026-5837 CVE-2026-44840 GHSA-q2m9-6jp9-c6mc
  • GO-2026-5929 CVE-2026-44342 GHSA-26v7-h57m-gh9m
  • GO-2026-5930 CVE-2026-33655 GHSA-6qcr-qxgr-m7fv
  • GO-2026-5933 GHSA-3g4q-2f67-2gvh
  • GO-2026-5934 GHSA-59qp-cfj3-rp64
  • GO-2026-5935 GHSA-7856-g3gv-9wq8
  • GO-2026-5936 CVE-2026-53552 GHSA-26rh-24rg-j3vv
  • GO-2026-5937 CVE-2026-53508 GHSA-2jcc-mxv7-p3f9
  • GO-2026-5938 CVE-2026-53553 GHSA-4g5x-hcwm-82jw
  • GO-2026-5939 CVE-2026-10517 GHSA-698x-9w2p-7vvp
  • GO-2026-5940 CVE-2026-53572 GHSA-6w3m-4hhp-775q
  • GO-2026-5941 CVE-2026-53487 GHSA-gvhc-wv3v-7pf8
  • GO-2026-5942 CVE-2026-46600
  • GO-2026-5944 CVE-2026-50197 GHSA-659f-rgp5-w4wf
  • GO-2026-5945 CVE-2026-6815 GHSA-rmxx-v9rj-vpvg
  • GO-2026-5946 CVE-2026-52831 GHSA-v5px-423j-pf7p
  • GO-2026-5947 CVE-2026-53649 GHSA-xqhv-chqm-fhcc
  • GO-2026-5948 CVE-2026-50554 GHSA-588f-fvcv-xhvf
  • GO-2026-5949 CVE-2026-50553 GHSA-rqrh-8wpv-x7hh
  • GO-2026-5950 CVE-2026-53602 GHSA-339v-266x-79xr
  • GO-2026-5951 CVE-2026-10219 GHSA-6jm8-4fhr-5w64
  • GO-2026-5952 CVE-2026-49834 GHSA-9vcr-p3rj-q5q6
  • GO-2026-5953 CVE-2026-9094 GHSA-c9w5-qp6m-m395
  • GO-2026-5956 CVE-2026-55252 GHSA-h5g6-xmh4-hc37
  • GO-2026-5957 CVE-2026-54158 GHSA-5xfx-xj4h-5p7r
  • GO-2026-5958 CVE-2026-54068 GHSA-gcm7-57gf-953c
  • GO-2026-5959 CVE-2026-54072 GHSA-h29v-hj44-q8cv
  • GO-2026-5961 CVE-2026-54069 GHSA-hvr9-72v2-fff3
  • GO-2026-5962 CVE-2026-54088 GHSA-m93h-4hw7-5qcm
  • GO-2026-5963 CVE-2026-54067 GHSA-mvjr-vv3c-w4qv
  • GO-2026-5964 CVE-2026-54066 GHSA-p4m3-mgmm-c664
  • GO-2026-5965 CVE-2026-54070 GHSA-w7cg-whh7-xp28
  • GO-2026-5966 CVE-2026-54089 GHSA-xqp3-jq6g-x3qm
  • GO-2026-5967 CVE-2026-50551 GHSA-56mp-4f3v-fgj2
  • GO-2026-5968 CVE-2026-54174 GHSA-fpg8-7664-jc5q
  • GO-2026-5969 GHSA-g936-7jqj-mwv8
  • GO-2026-5970 CVE-2026-56852
  • GO-2026-5973 CVE-2026-54250 GHSA-jxr7-mqhw-9p98
  • GO-2026-5974 CVE-2026-44300 GHSA-wmj8-9953-vff5
  • GO-2026-5975 CVE-2026-50018 GHSA-42j2-w334-qxw7
  • GO-2026-5976 CVE-2026-50141 GHSA-g7mm-9vx7-jm7h
  • GO-2026-5977 CVE-2026-50013 GHSA-qrh4-p6v4-mrfg
  • GO-2026-5978 CVE-2026-50125 GHSA-qw5r-ppcg-f8rj
  • GO-2026-5979 CVE-2026-50006 GHSA-xrcf-6jh3-ggvx
  • GO-2026-5980 CVE-2026-50158 GHSA-2c7f-fxww-6w6c
  • GO-2026-5981 GHSA-mqxv-9rm6-w8qc
  • GO-2026-5982 GHSA-pqg7-v6wh-3pfp
  • GO-2026-5984 CVE-2026-53604 GHSA-2p2f-px33-4vv5
  • GO-2026-5985 GHSA-7rx3-5wx3-5v76
  • GO-2026-5986 CVE-2026-61699 GHSA-cm26-5974-52h8
  • GO-2026-5987 CVE-2026-55513 GHSA-g4x6-jcvr-9m3g
  • GO-2026-5988 CVE-2026-54628 GHSA-hwrq-8wxh-q4xv
  • GO-2026-5989 CVE-2026-55512 GHSA-m3cx-mwpg-32jg
  • GO-2026-5990 CVE-2026-54629 GHSA-mf78-3rpf-r784
  • GO-2026-5991 CVE-2026-53603 GHSA-q4vm-pq3q-8wgq
  • GO-2026-5992 CVE-2026-61549 GHSA-qf34-295c-26v8
  • GO-2026-5996 CVE-2026-54450 GHSA-pph6-vfjv-vpjw
  • GO-2026-5997 CVE-2026-54452 GHSA-xgch-x3mx-cm3c
  • GO-2026-5998 CVE-2026-54495 GHSA-398h-7f66-3h4p
  • GO-2026-5999 CVE-2026-10814 GHSA-jh6h-v6mp-h22v
  • GO-2026-6002 CVE-2026-58196 GHSA-pr64-jmmf-jp54
  • GO-2026-6003 CVE-2026-53714 GHSA-22xc-xg2r-9j7v
  • GO-2026-6004 CVE-2026-52833 GHSA-3v79-m2cg-89ww
  • GO-2026-6005 CVE-2026-53715 GHSA-8fv2-88gg-hm7q
  • GO-2026-6006 CVE-2026-53716 GHSA-cxpq-8v7q-cg56 *…
Record
openSUSE-SU-2026:21483-1
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
github.com/nezhahq/nezha
Go
 1.0.0 up to 2.2.0
2.2.0
github.com/nezhahq/nezha
Go
 1.0.0 and later None known
govulncheck-vulndb
openSUSE:Leap 16.0
From an advisory covering 1734 CVEs
 before 0.0.20260723T184607-160000.1.1
0.0.20260723T184607-160000.1.1

History

History
RecordedChangedSources
affected, facts
first indexedCVE List, EUVD, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2026-53523 is a medium vulnerability (CVSS 6.8) in Nezhahq Nezha, published June 12, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.29%, the 21st percentile. Fixed in github.com/nezhahq/nezha 2.2.0.

References

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