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Moderate severityNVD Advisory· Published Dec 11, 2020· Updated Aug 4, 2024

LES Server DoS via GetProofsV2

CVE-2020-26264

Description

Go Ethereum, or "Geth", is the official Golang implementation of the Ethereum protocol. In Geth before version 1.9.25 a denial-of-service vulnerability can make a LES server crash via malicious GetProofsV2 request from a connected LES client. This vulnerability only concerns users explicitly enabling les server; disabling les prevents the exploit. The vulnerability was patched in version 1.9.25.

Affected packages

Versions sourced from the GitHub Security Advisory.

PackageAffected versionsPatched versions
github.com/ethereum/go-ethereumGo
< 1.9.251.9.25

Affected products

1

Patches

1
bddd103a9f0a

les: fix GetProofsV2 bug (#21896)

https://github.com/ethereum/go-ethereumFelföldi ZsoltNov 24, 2020via ghsa
commit
1 file changed · +2 −4
  • les/server_handler.go+2 −4 modified
    @@ -610,6 +610,7 @@ func (h *serverHandler) handleMsg(p *clientPeer, wg *sync.WaitGroup) error {
 		var (
 			lastBHash common.Hash
 			root      common.Hash
+			header    *types.Header
 		)
 		reqCnt := len(req.Reqs)
 		if accept(req.ReqID, uint64(reqCnt), MaxProofsFetch) {
@@ -624,10 +625,6 @@ func (h *serverHandler) handleMsg(p *clientPeer, wg *sync.WaitGroup) error {
 						return
 					}
 					// Look up the root hash belonging to the request
-					var (
-						header *types.Header
-						trie   state.Trie
-					)
 					if request.BHash != lastBHash {
 						root, lastBHash = common.Hash{}, request.BHash
 
@@ -654,6 +651,7 @@ func (h *serverHandler) handleMsg(p *clientPeer, wg *sync.WaitGroup) error {
 					// Open the account or storage trie for the request
 					statedb := h.blockchain.StateCache()
 
+					var trie state.Trie
 					switch len(request.AccKey) {
 					case 0:
 						// No account key specified, open an account trie

Vulnerability mechanics

Generated by null/stub on May 9, 2026. Inputs: CWE entries + fix-commit diffs from this CVE's patches. Citations validated against bundle.

References

7

News mentions

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