CVE-2020-26264
LES Server DoS via GetProofsV2
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
LES Server DoS via GetProofsV2
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.
- Record
CVE-2020-26264- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-400
- Updated
- 2026-11-02
EUVDEUVD-2021-1389
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.
- Record
EUVD-2021-1389- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-03
GitHub AdvisoriesGHSA-r33q-22hv-j29q
Denial of service in github.com/ethereum/go-ethereum
Impact
A DoS vulnerability can make a LES server crash via malicious GetProofsV2 request from a connected LES client.
Patches
The vulnerability was patched in https://github.com/ethereum/go-ethereum/pull/21896.
Workarounds
This vulnerability only concerns users explicitly enabling les server; disabling les prevents the exploit.
It can also be patched by manually applying the patch in https://github.com/ethereum/go-ethereum/pull/21896.
For more information
If you have any questions or comments about this advisory:
- Open an issue in go-ethereum
- Email us at [email protected]
- Record
GHSA-r33q-22hv-j29q- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-400
- Updated
- 2026-11-02
NVD
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.
- Record
CVE-2020-26264- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H - CVSS 2.0
- 4.0 Medium
AV:N/AC:L/Au:S/C:N/I:N/A:P - Weakness
- CWE-400
- Updated
- 2026-11-02
OSV
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.
- Record
CVE-2020-26264- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
OSVGHSA-r33q-22hv-j29q
Denial of service in github.com/ethereum/go-ethereum
Impact
A DoS vulnerability can make a LES server crash via malicious GetProofsV2 request from a connected LES client.
Patches
The vulnerability was patched in https://github.com/ethereum/go-ethereum/pull/21896.
Workarounds
This vulnerability only concerns users explicitly enabling les server; disabling les prevents the exploit.
It can also be patched by manually applying the patch in https://github.com/ethereum/go-ethereum/pull/21896.
For more information
If you have any questions or comments about this advisory:
- Open an issue in go-ethereum
- Email us at [email protected]
- Record
GHSA-r33q-22hv-j29q- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-400
- Updated
- 2026-11-02
OSVGO-2021-0063 No score
Nil pointer dereference via malicious RPC message in github.com/ethereum/go-ethereum
Due to a nil pointer dereference, a maliciously crafted RPC message can cause a panic. If handling RPC messages from untrusted clients, this may be used as a denial of service vector.
- Record
GO-2021-0063- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
github.com/ethereum/go-ethereumGo |
before 1.9.25 | 1.9.25 |
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2020-26264 is a medium vulnerability (CVSS 6.5) in Ethereum Go Ethereum, published December 11, 2020. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.89%, the 79th percentile. Fixed in github.com/ethereum/go-ethereum 1.9.25.
References
github.com/ethereum/go-ethereum/security/advisories/GHSA-r33q-22hv-j29q
nvd.nist.gov/vuln/detail/CVE-2020-26264
pkg.go.dev/vuln/GO-2021-0063