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CVE-2026-63075

INDEX BUILT · 2026-09-20

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QUIC ACK-only Packet Retention Can Cause Memory Exhaustion

CVE-2026-630754 of 4 sources documented this
5

rank 5 = 0 + 0 + 0 + 5 + 0

rank@v1 · backlog

Someone is already using it

CISA KEV catalog · public proof-of-concept · FIRST EPSS

EPSS 0.00480  ·  without this subject the record ranks 5

What it costs you if it fires

NVD CVSS base score, then the CNA's own

no CVSS held by anyone  ·  without this subject the record ranks 5

It is getting worse, not staying still

FIRST EPSS series, rescorings and bad loads removed

no persisting rise in 365 days  ·  without this subject the record ranks 5

How much of the world it touches

NVD CPE configurations

4 products in the CPE ranges  ·  without this subject the record ranks 0

Someone else already set the date

CISA KEV remediation due date

no CISA due date  ·  without this subject the record ranks 5

Hindsight · the state

0.0048EPSSNOT IN KEVas of 2026-09-20
Severitynot scored
Harmnot stated
Exploitationnone in held sources
Defensefix version namedreceipt
Movementone observationreceipt
SINGLE READINGOne observation held. There is no shape yet. arc-rules@v1

Foresight · where to check next

This record is one instance of CWE-770, allocation of resources without limits or throttling. The index holds 2390 prior instances of this class, 2 KEV-listed. taxonomy@v1

Full pattern panel

Color is a claim, not decoration:the hostile worldthe defenseno signal

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Harm, if it fires from the vector and the weakness

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ReachNo CVSS vector in held sources, so no reach or impact can be stated.
Weakness classCWE-770 Allocation of Resources Without Limits or Throttlingreceipt
Published consequencesCWE-770: Availability: DoS: Resource Consumption (CPU), DoS: Resource Consumption (Memory), DoS: Resource Consumption (Other)[email protected]

CISA KEV & Federal Remediation Deadline from the record and CISA

The fix, and how long it's been waiting.

Fixed in4.0.2; 3.6.4; 3.5.8; 3.4.7receipt
Patch available sinceNo dated patch-availability record in held sources. The index holds reference URLs without dates and only the current revision of the CVE record, so the day a fix first existed cannot be derived. Only the versions it landed in.

Exploit Status & Known PoCs a ladder, not a score

Current rung: Nothing observed in held sources.

  • RUNG 1Nothing observed in held sources
  • RUNG 2Proof-of-concept published
  • RUNG 3Exploited in the wild · CISA KEV listed
  • RUNG 4Ransomware campaign use known

Authority who says so

Exploit probability0.0048 · top 59% of all CVEsreceipt
Blast breadth1 product across 1 vendorderived
Assigned byopensslreceipt
Recorded changes1 · last 19 Sep 2026derived

Affected & Fixed Versions as published

Affected productOpenSSLreceipt
Published rangesopenssl >= 3.4.0 < 3.4.7; openssl >= 3.5.0 < 3.5.8; openssl >= 3.6.0 < 3.6.4; openssl >= 4.0.0 < 4.0.2receipt
Fixed in4.0.2; 3.6.4; 3.5.8; 3.4.7receipt

A rung lights from a row in the index, never from an assessment. "Held sources" is the true scope of the claim: this index reads the CVE record, NVD, CISA KEV, FIRST's EPSS and public proof-of-concept repositories, and it does not observe attacks.

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What it is stated by the CNA

Issue summary: When OpenSSL processes QUIC traffic from a peer that repeatedly sends ack-eliciting packets while not acknowledging ACK-only responses, the QUIC stack can retain ACK-only packet metadata for the lifetime of the connection. Impact summary: A remote peer that can complete a QUIC handshake can cause connection-scoped memory growth which may lead to Denial of Service through memory exhaustion, especially with sustained traffic or many concurrent QUIC connections. CWE: CWE-770: Allocation of Resources Without Limits or Throttling Description: When the OpenSSL QUIC stack sends an ACK-only packet, there is no requirement by the QUIC protocol that the peer will acknowledge that ACK receipt

Read the rest of the CNA's description

-only packet (i.e. it is itself not ack-eliciting). However, the OpenSSL implementation stores the metadata about the ACK frames regardless. In and of itself that's ok, but if a malicious peer establishes a connection, and then drives the connection such that ACK-only packets are forced from the OpenSSL implementation peer (i.e., by sending numerous PING frames), and then withholding any subsequent acks for ack-eliciting data, like legitimate data, said malicious peer can force inappropriate memory growth on the OpenSSL peer, potentially leading to a Denial of Service. The fix is to ensure that we account for the transmission of the ACK-only packet in the packet histories high and low watermark without actually storing the ACK-only packet metadata itself. FIPS impact: no The OpenSSL FIPS module is not affected as the QUIC code is outside the FIPS module boundary.

NVD's analysis a second authority

weakness
CWE-770
affected versions
openssl >= 3.4.0 < 3.4.7; openssl >= 3.5.0 < 3.5.8; openssl >= 3.6.0 < 3.6.4; and 1 more, listed in full below
also scored by
7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

check it yourself openssl-library.org github.com github.com github.com github.com receipt

Movement

Only one observation of this value is held, so there is no movement to show yet.

The full biography

Published2026-08-25Index as of2026-08-28

The record had been public for 3 days when this index was last written.

Published 2026-08-25 receipt · Index as of 2026-08-28 derived

The pattern, elsewhere

This record is one instance of CWE-770, allocation of resources without limits or throttling. The index holds 2390 prior instances of this class, 2 KEV-listed. [email protected]

CVE-2020-3566 · Cisco IOS XR Softwareonly 1 attribute comparableKEV listed · 2020receipt
CVE-2020-3569 · Cisco IOS XR Softwareonly 1 attribute comparableKEV listed · 2020receipt

2390 records in this class held. The six above are ranked by exploit maturity, then recency.

Siblings and hubs

Records related to this one

Its defect family

openssl

Of the 4 records in this family, this is the only one holding a stated fix version: 4.0.2; 3.6.4; 3.5.8; 3.4.7.

Grouped by shared product and weakness, not by shared vulnerability. Each record's own state is on its own page.

Family membership: held values

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What usually comes next

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