{"answers":{"affected":"3 open source packages ship an affected version, including github.com/bishopfox/sliver.","exploited":"There is no known exploitation of GHSA-c279-989m-238f in the wild and no public exploit code.","fix":"No fix has been published for GHSA-c279-989m-238f yet. Limit exposure of the affected software until one is available.","what":"GHSA-c279-989m-238f is a vulnerability in github.com/bishopfox/sliver, published on 29 Mar 2026. Any signed-in user can exploit it over the network, with no action from the victim."},"fix_prompt":"Check this codebase for GHSA-c279-989m-238f and fix it if it is affected.\n\nWhat it is: GHSA-c279-989m-238f is a vulnerability in github.com/bishopfox/sliver, published on 29 Mar 2026. Any signed-in user can exploit it over the network, with no action from the victim.\nExploitation: There is no known exploitation of GHSA-c279-989m-238f in the wild and no public exploit code.\n\nAffected packages and fixed versions:\n- github.com/bishopfox/sliver (Go): affected all versions; no fix listed\n- github.com/bishopfox/sliver (Go): affected all versions up to 1.7.3; no fix listed\n- github.com/bishopfox/sliver (Go): affected all versions up to 1.7.3; no fix listed\n\nTask:\n1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.\n2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.\n3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.\n4. Run the tests and summarise what changed and why.\n5. If nothing in the project is affected, say so and change nothing.\n\nReference: https://insights.sbomify.com/GHSA-c279-989m-238f/ (Markdown: https://insights.sbomify.com/GHSA-c279-989m-238f/index.md)","id":"GHSA-c279-989m-238f","markdown":"https://insights.sbomify.com/GHSA-c279-989m-238f/index.md","name":"GHSA-c279-989m-238f","record":{"aliases":["GO-2026-4899"],"analysis":{"component_type":"server_software","fix_type":"patch","impacts":["denial_of_service"],"network_reachable":"yes","non_default_config":false,"product_category":"C2 server software","requires_auth":"low_privilege","summary":"An authenticated implant can trigger a server panic via reverse tunnel closure, causing denial of service.","user_interaction":"not_required","vuln_class":"null_dereference"},"analysis_generated_by":"qwen3.8-flash-next","assigner":null,"cpe":[],"cvss":{"score":null,"severity":null,"source":null,"vector":null,"version":null},"cwes":[],"description":"### Summary\nA nil pointer dereference in `tunnelCloseHandler` causes the handler goroutine to panic whenever a reverse tunnel (rportfwd) close is attempted. Both the legitimate close path AND the unauthorized close path dereference `tunnel.SessionID` where `tunnel` is guaranteed nil. This means rportfwd tunnels can never be cleanly closed, and any authenticated implant can trigger repeated goroutine panics.\n\n### Details\nFile: `server/handlers/sessions.go` lines 172 and 175\n\nThe function enters an `else` block precisely because `core.Tunnels.Get(tunnelData.TunnelID)` returned `nil`. Both conditions inside that else block then dereference `tunnel.SessionID` instead of `rtunnel.SessionID`:\n```go\n} else {\n    rtunnel := rtunnels.GetRTunnel(tunnelData.TunnelID)\n\n    if rtunnel != nil \u0026\u0026 session.ID == tunnel.SessionID {      // LINE 172 — nil deref\n        rtunnel.Close()\n        rtunnels.RemoveRTunnel(rtunnel.ID)\n    } else if rtunnel != nil \u0026\u0026 session.ID != tunnel.SessionID { // LINE 175 — nil deref\n        sessionHandlerLog.Warnf(\"...\")\n    }\n}\n```\n\nNote: The identical bug was already fixed in `tunnelDataHandler` at lines 124/126 (correctly uses `rtunnel.SessionID`), but the fix was \nnot applied to `tunnelCloseHandler`.\n\n### PoC\n```go\ntunnel := GetTunnel(999)   // returns nil — no normal tunnel with this ID\n// tunnel is nil here\n\nrtunnel := GetRTunnel(999) // returns valid rtunnel owned by session-AAAA\n\n// Both lines below panic with:\n// runtime error: invalid memory address or nil pointer dereference\nif rtunnel != nil \u0026\u0026 sessionID == tunnel.SessionID { ... }      // line 172\n} else if rtunnel != nil \u0026\u0026 sessionID != tunnel.SessionID { ... } // line 175\n```\n\nConfirmed on master commit `7ac4db3fa` with standalone reproducer.\nOutput:\n```\nPANIC on line 172 (legitimate close): runtime error: invalid memory address or nil pointer dereference\nPANIC on line 175 (unauthorized close): runtime error: invalid memory address or nil pointer dereference\n```\n\n![1](https://github.com/user-attachments/assets/93b24286-3282-454f-80a4-b01abe4f1d63)\n![2](https://github.com/user-attachments/assets/d4219aea-eb18-474c-b69a-a5e20e97161f)\n![3](https://github.com/user-attachments/assets/5a76b0d7-ae5b-4d91-bfe9-730d3e5c322c)\n\n### Impact\n- rportfwd tunnels **cannot be closed** — functional regression\n- Any authenticated implant can trigger repeated handler goroutine panics\n- rtunnel map entries leak (never cleaned up on close failure)\n- `recoverAndLogPanic()` prevents full server crash but silently drops the close operation\n\n### Fix\nReplace `tunnel.SessionID` with `rtunnel.SessionID` on both lines:\n```diff\n-  if rtunnel != nil \u0026\u0026 session.ID == tunnel.SessionID {\n+  if rtunnel != nil \u0026\u0026 session.ID == rtunnel.SessionID {\n       rtunnel.Close()\n       rtunnels.RemoveRTunnel(rtunnel.ID)\n-  } else if rtunnel != nil \u0026\u0026 session.ID != tunnel.SessionID {\n+  } else if rtunnel != nil \u0026\u0026 session.ID != rtunnel.SessionID {\n```","ecosystems":["Go"],"exploits":{"exploitdb":null,"first_seen":null,"github_poc":null,"max_poc_stars":null,"metasploit":null,"nuclei":null,"refs":[],"tier":null},"has_fix":false,"headline":"Sliver: Nil Pointer Dereference in tunnelCloseHandler causes panic when a reverse tunnel (rportfwd) close is attempted","id":"GHSA-c279-989m-238f","indexable":true,"kev":null,"kind":"advisory","links":{"ecosystem":"Go","product":null,"products":[],"type":"null_dereference","year":"2026"},"n_packages":3,"n_references":null,"packages":[{"ecosystem":"Go","fixed":[],"introduced":["0"],"last_affected":[],"package":"github.com/bishopfox/sliver","purl":"pkg:golang/github.com/bishopfox/sliver","source":"GO-2026-4899"},{"ecosystem":"Go","fixed":[],"introduced":["0"],"last_affected":["1.7.3"],"package":"github.com/bishopfox/sliver","purl":null,"source":"GHSA-c279-989m-238f"},{"ecosystem":"Go","fixed":[],"introduced":["0"],"last_affected":["1.7.3"],"package":"github.com/bishopfox/sliver","purl":"pkg:golang/github.com/bishopfox/sliver","source":"GHSA-c279-989m-238f"}],"products":null,"published":"2026-03-29","related":[],"sources":[{"class":"attribution","licence":"CC BY 4.0","name":"GitHub Advisory Database","prefix":"GHSA"},{"class":"attribution","licence":"CC BY 4.0","name":"Go Vulnerability Database","prefix":"GO"}],"ssvc":{"automatable":null,"exploitation":null,"technical_impact":null},"state":null,"updated":null,"vendors":null},"summary":"An authenticated implant can trigger a server panic via reverse tunnel closure, causing denial of service.","url":"https://insights.sbomify.com/GHSA-c279-989m-238f/"}