CVE-2026-48599Authorization bypass via path binding override in elixir-grpc/grpc HTTP transcoding
- 7.6HighCVSS base score
- 0.34%Exploitation in 30 daysEPSS · top 72% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- YesPublic exploitsa reference or SSVC says so
Description
Authorization Bypass Through User-Controlled Key vulnerability in elixir-grpc grpc allows authenticated attackers to access or modify resources belonging to other users by smuggling a conflicting value for any path-bound field via the query string or request body. In 'Elixir.GRPC.Server.Transcode':map_request/5 (lib/grpc/server/transcode.ex), all three clauses use Map.merge/2 with path bindings as the first argument, giving them the lowest merge precedence. A request such as GET /users/me/profile?user_id=victim (or a POST with {"user_id": "victim"} when body: "*") yields a decoded protobuf struct where the path-bound field carries the attacker-supplied value rather than the router-extracted value. Any handler that uses the path-bound field for authorization, multi-tenancy scoping, or ownership checks is silently bypassed. This issue affects grpc: from 0.8.0 before 1.0.0.
Public exploit
An exploit or proof of concept is public: anyone can try it against an unpatched system. A reference of the record is tagged as an exploit. CISA's SSVC rates its exploitation: a proof of concept is public.
Show the exploits1
References tagged exploit1 reference
- https://github.com/elixir-grpc/grpc/security/advisories/GHSA-mwr4-5g34-j5cq (opens in a new tab)vendor-advisoryrelatedexploit
Timeline
ID reserved
By EEF
- 24 days later
· 24 days later
Published
- 3 months later
· 3 months later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| EEFCNA (assigner) | 4.0 | High7.6 | CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N |
| NVDNVD · Deferred | 4.0 | High7.6 | CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X |
- EPSS (exploitation in 30 days)
- 0.34% · top 72% of all CVEs (13 Nov 2026)
- CISA SSVC
- Exploitation: poc · Automatable: no · Technical impact: total
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.6.
Affected products
- affected 0.8.0 – < 1.0.0
- affected 8aaf3d3a8c4c7b08ac65e9c6f254e0d24da1d048 – < 33b6a095dbc91c6dee3c7b90893d7d74952e82e4
Affected packages
From reviewed advisories of the GitHub Advisory Database.
References
References5
- https://github.com/elixir-grpc/grpc/security/advisories/GHSA-mwr4-5g34-j5cq (opens in a new tab)vendor-advisoryrelatedexploit
- EEF CNA record for CVE-2026-48599 (opens in a new tab)related
- OSV record EEF-CVE-2026-48599 (opens in a new tab)related
- Introducing commit 8aaf3d3 in elixir-grpc/grpc (opens in a new tab)related
- Fix commit 33b6a09 in elixir-grpc/grpc (opens in a new tab)patch
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-37013 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisory GHSA-mwr4-5g34-j5cq (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2026-48599)Record last updated .