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CVE-2023-6193

Unbounded queuing of path validation messages in cloudflare-quiche

5.3 MediumFix available

quiche v. 0.15.0 through 0.19.0 was discovered to be vulnerable to unbounded queuing of path validation messages, which could lead to excessive resource consumption. QUIC path validation (RFC 9000 Section 8.2) requires that the recipient of a PATH_CHALLENGE frame responds by sending a PATH_RESPONSE. An unauthenticated remote attacker can exploit the vulnerability by sending PATH_CHALLENGE frames and manipulating the connection (e.g. by restricting the peer's congestion window size) so that PATH_RESPONSE frames can only be sent at the slower rate than they are received; leading to storage of path validation data in an unbounded queue. Quiche versions greater than 0.19.0 address this problem.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
Low
Privileges needed
None
User interaction
None

What an attacker can affect

Confidentiality
None
Integrity
None
Availability
Low

Exploit likelihood

0.76%Up 0.7 points since Dec 13, 2023
90%50%10%1%

What each source reports

CVE List Score used 5.3

Unbounded queuing of path validation messages in cloudflare-quiche

quiche v. 0.15.0 through 0.19.0 was discovered to be vulnerable to unbounded queuing of path validation messages, which could lead to excessive resource consumption. QUIC path validation (RFC 9000 Section 8.2) requires that the recipient of a PATH_CHALLENGE frame responds by sending a PATH_RESPONSE. An unauthenticated remote attacker can exploit the vulnerability by sending PATH_CHALLENGE frames and manipulating the connection (e.g. by restricting the peer's congestion window size) so that PATH_RESPONSE frames can only be sent at the slower rate than they are received; leading to storage of path validation data in an unbounded queue. Quiche versions greater than 0.19.0 address this problem.

Record
CVE-2023-6193
CVSS 3.1
5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Weakness
CWE-400
Updated
2026-11-02
EUVDEUVD-2023-3306 5.3

quiche v. 0.15.0 through 0.19.0 was discovered to be vulnerable to unbounded queuing of path validation messages, which could lead to excessive resource consumption. QUIC path validation (RFC 9000 Section 8.2) requires that the recipient of a PATH_CHALLENGE frame responds by sending a PATH_RESPONSE. An unauthenticated remote attacker can exploit the vulnerability by sending PATH_CHALLENGE frames and manipulating the connection (e.g. by restricting the peer's congestion window size) so that PATH_RESPONSE frames can only be sent at the slower rate than they are received; leading to storage of path validation data in an unbounded queue. Quiche versions greater than 0.19.0 address this problem.

Record
EUVD-2023-3306
CVSS 3.1
5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Updated
2026-11-03
GitHub AdvisoriesGHSA-w3vp-jw9m-f9pm 5.3

Unbounded queuing of path validation messages in cloudflare-quiche

Impact

quiche v. 0.15.0 through 0.19.0 was discovered to be vulnerable to unbounded queuing of path validation messages, which could lead to excessive resource consumption.

QUIC path validation (RFC 9000 Section 8.2) requires that the recipient of a PATH_CHALLENGE frame responds by sending a PATH_RESPONSE. An unauthenticated remote attacker can exploit the vulnerability by sending PATH_CHALLENGE frames and manipulating the connection (e.g. by restricting the peer's congestion window size) so that PATH_RESPONSE frames can only be sent at the slower rate than they are received, leading to storage of path validation data in an unbounded queue.

Patches

Quiche versions greater than 0.19.0 address this problem.

References

CVE-2023-6193 RFC 9000 Section 8.2

Record
GHSA-w3vp-jw9m-f9pm
CVSS 3.1
5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Weakness
CWE-400
Updated
2026-11-02
NVD 5.3

quiche v. 0.15.0 through 0.19.0 was discovered to be vulnerable to unbounded queuing of path validation messages, which could lead to excessive resource consumption. QUIC path validation (RFC 9000 Section 8.2) requires that the recipient of a PATH_CHALLENGE frame responds by sending a PATH_RESPONSE. An unauthenticated remote attacker can exploit the vulnerability by sending PATH_CHALLENGE frames and manipulating the connection (e.g. by restricting the peer's congestion window size) so that PATH_RESPONSE frames can only be sent at the slower rate than they are received; leading to storage of path validation data in an unbounded queue. Quiche versions greater than 0.19.0 address this problem.

Record
CVE-2023-6193
CVSS 3.1
5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Weakness
CWE-400
Updated
2026-11-02
OSV 5.3

Unbounded queuing of path validation messages in cloudflare-quiche

quiche v. 0.15.0 through 0.19.0 was discovered to be vulnerable to unbounded queuing of path validation messages, which could lead to excessive resource consumption. QUIC path validation (RFC 9000 Section 8.2) requires that the recipient of a PATH_CHALLENGE frame responds by sending a PATH_RESPONSE. An unauthenticated remote attacker can exploit the vulnerability by sending PATH_CHALLENGE frames and manipulating the connection (e.g. by restricting the peer's congestion window size) so that PATH_RESPONSE frames can only be sent at the slower rate than they are received; leading to storage of path validation data in an unbounded queue. Quiche versions greater than 0.19.0 address this problem.

Record
CVE-2023-6193
CVSS 3.1
5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Weakness
CWE-400
Updated
2026-11-02
OSVGHSA-w3vp-jw9m-f9pm 5.3

Unbounded queuing of path validation messages in cloudflare-quiche

Impact

quiche v. 0.15.0 through 0.19.0 was discovered to be vulnerable to unbounded queuing of path validation messages, which could lead to excessive resource consumption.

QUIC path validation (RFC 9000 Section 8.2) requires that the recipient of a PATH_CHALLENGE frame responds by sending a PATH_RESPONSE. An unauthenticated remote attacker can exploit the vulnerability by sending PATH_CHALLENGE frames and manipulating the connection (e.g. by restricting the peer's congestion window size) so that PATH_RESPONSE frames can only be sent at the slower rate than they are received, leading to storage of path validation data in an unbounded queue.

Patches

Quiche versions greater than 0.19.0 address this problem.

References

CVE-2023-6193 RFC 9000 Section 8.2

Record
GHSA-w3vp-jw9m-f9pm
CVSS 3.1
5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Weakness
CWE-400
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
quiche
crates.io
0.15.0 up to 0.19.1
0.19.1

History

History
RecordedChangedSources
aliases, publishedEUVD
first indexedCVE List, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2023-6193 is a medium vulnerability (CVSS 5.3) in Cloudflare Quiche, published December 12, 2023. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.76%, the 55th percentile. Fixed in quiche 0.19.1.

References

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