coturn — security advisory
Coturn is a free open source implementation of TURN and STUN Server. Versions prior to 4.10.0 contain a stack buffer overflow in decode_oauth_token_gcm(). A uint16_t nonce_len field read from an attacker-supplied OAuth access token (0-65535) is passed directly to memcpy() as the copy length into a 256-byte stack buffer (oauth_encrypted_block.nonce[256]) without bounds checking. The overflow occurs before AES-GCM authentication is verified, the attacker does not need to know the OAuth key or produce a valid AES-GCM token. Up to 735 bytes of attacker-controlled data are written past the buffer, may corrupt adjacent stack data, including control-flow data depending on compiler, ABI, and mitigations. Requires --oauth mode (non-default). This may provide a plausible RCE primitive depending on exploit mitigations; because coturn is widely deployed for WebRTC TURN/STUN and --oauth is commonly recommended, impact can be broad. This issue has been fixed in version 4.10.0.
- Products
- coturn
- Affected versions
- 4.12.0-1, 4.14.0-1, 4.15.0-1, 4.18.0-1, 4.6.1-1, 4.6.1-2
- Fixed versions
- 4.12.0-1
- CVEs
- CVE-2026-43994
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 29 Oct 2026, 13:52 UTC · Revision 1
Source evidence
Coturn is a free open source implementation of TURN and STUN Server. Versions prior to 4.10.0 contain a stack buffer overflow in decode_oauth_token_gcm(). A uint16_t nonce_len field read from an attacker-supplied OAuth access token (0-65535) is passed directly to memcpy() as the copy length into a 256-byte stack buffer (oauth_encrypted_block.nonce[256]) without bounds checking. The overflow occurs before AES-GCM authentication is verified, the attacker does not need to know the OAuth key or produce a valid AES-GCM token. Up to 735 bytes of attacker-controlled data are written past the buffer, may corrupt adjacent stack data, including control-flow data depending on compiler, ABI, and mitigations. Requires --oauth mode (non-default). This may provide a plausible RCE primitive depending on exploit mitigations; because coturn is widely deployed for WebRTC TURN/STUN and --oauth is commonly recommended, impact can be broad. This issue has been fixed in version 4.10.0.
osv:DEBIAN-CVE-2026-43994
coturn
Fixed versions: Not specified
coturn
Fixed versions: Not specified
coturn
Fixed versions: 4.12.0-1
Complete source record
{
"id": "7473e73cdfb7f6dfdb09ae003ca9c0694e6033cf5e1465843b4283980339740e",
"url": "https://osv.dev/vulnerability/DEBIAN-CVE-2026-43994",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "DEBIAN-CVE-2026-43994",
"summary": "Coturn is a free open source implementation of TURN and STUN Server. Versions prior to 4.10.0 contain a stack buffer overflow in decode_oauth_token_gcm(). A uint16_t nonce_len field read from an attacker-supplied OAuth access token (0-65535) is passed directly to memcpy() as the copy length into a 256-byte stack buffer (oauth_encrypted_block.nonce[256]) without bounds checking. The overflow occurs before AES-GCM authentication is verified, the attacker does not need to know the OAuth key or produce a valid AES-GCM token. Up to 735 bytes of attacker-controlled data are written past the buffer, may corrupt adjacent stack data, including control-flow data depending on compiler, ABI, and mitigations. Requires --oauth mode (non-default). This may provide a plausible RCE primitive depending on exploit mitigations; because coturn is widely deployed for WebRTC TURN/STUN and --oauth is commonly recommended, impact can be broad. This issue has been fixed in version 4.10.0.",
"evidence": "osv:DEBIAN-CVE-2026-43994",
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],
"modified": "2026-10-10T16:00:06.544462889Z",
"provider": "osv",
"upstream": [
"CVE-2026-43994"
],
"references": [
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]
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"related_cves": [
{
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"evidence": "/upstream"
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],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 250469,
"published_at": "2026-06-18T21:16:28.63+00:00"
}