Skip to main content
No exploitation reportedFix available

CVE-2026-34183

Unbounded Memory Growth in the QUIC PATH_CHALLENGE Handler

No exploitation reported by the sources we read.

  • Published2026-06-09
  • Fixed in3.6.3 · 3.5.7 · 3.4.6
  • WeaknessCWE-1325

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

Issue summary: Remote peer may exhaust heap memory of the QUIC server or client by flooding it with packets containing PATH_CHALLENGE frames. Impact summary: A malicious remote peer can cause an unbounded memory allocation which can lead to an abnormal termination of the application acting as a QUIC client or server and a Denial of Service. A remote peer may exhaust heap memory by flooding the local QUIC stack with PATH_CHALLENGE frames. The local QUIC stack allocates a PATH_RESPONSE frame for every PATH_CHALLENGE it receives. The allocated PATH_RESPONSE frame gets freed only when the remote peer acknowledges reception of the PATH_RESPONSE frame which will not be done by a malicious peer. The FIPS modules in 4.0, 3.6, 3.5, 3.4, and 3.0 are not affected by this issue. The QUIC stack is outside of OpenSSL FIPS module boundary.

Timeline

dates in UTC
  1. 2026-06-0917:17CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 18:48 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2026-34183?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2026-34183?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD
OpenSSL
BranchAffectedFixed in
3.6≥ 3.6.0, < 3.6.33.6.3
3.5≥ 3.5.0, < 3.5.73.5.7
3.4≥ 3.4.0, < 3.4.63.4.6
4.0= 4.0.0no fix published

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • opensslAlmaLinux:10all versions · fixed in 1:3.5.5-4.el10_2.alma.1and 3 other packages
  • opensslAlmaLinux:9all versions · fixed in 1:3.5.5-4.el9_8and 3 other packages

Vendor advisories

  • CVE-2026-34183 Red Hat Product Security283 products fixed · 2 known affected

    openssl: Unbounded Memory Growth in the QUIC PATH_CHALLENGE Handler

    openshift/ose-rhel-coreos-8 as a component of Red Hat OpenShift Container Platform 4 · openshift/ose-rhel-coreos-9 as a component of Red Hat OpenShift Container Platform 4

  • RHSA-2026:83617 Red Hat Product Security39 products fixed

    Red Hat Security Advisory: openssl security update

  • RHSA-2026:82888 Red Hat Product Security1 product fixed

    Red Hat Security Advisory: cert-manager Operator for Red Hat OpenShift 1.17.2

  • RHSA-2026:82857 Red Hat Product Security1 product fixed

    Red Hat Security Advisory: cert-manager Operator for Red Hat OpenShift 1.18.2

  • RHSA-2026:82372 Red Hat Product Security4 products fixed

    Red Hat Security Advisory: cert-manager Operator for Red Hat OpenShift 1.18.2

  • RHSA-2026:82354 Red Hat Product Security4 products fixed

    Red Hat Security Advisory: cert-manager Operator for Red Hat OpenShift 1.18.2

20 more advisories

Full record on NVD

Fix

  1. Update OpenSSL to 3.6.3 · 3.5.7 · 3.4.6
  2. Vendor fix Red Hat Product Security RHSA-2026:83617 · 39 productsFor details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
  3. Vendor fix Red Hat Product Security RHSA-2026:82888 · 1 productBefore applying this update, make sure all previously released errata relevant to your system have been applied. The steps to apply the upgraded images are different depending on the installation plan approval policy you used when installing the cert-manager Operator for Red Hat OpenShift. - If t…
  4. Vendor fix Red Hat Product Security RHSA-2026:67551 · 3 productsFor details on how to apply this update, which includes the changes described in this advisory, refer to: https://images.redhat.com/
  5. Vendor fix Red Hat Product Security RHSA-2026:58981 · 3 productsPlease consult the RHUI Technology Preview Release Notes at https://access.redhat.com/articles/7141172 for instructions on how to use this image set.
  6. Vendor fix Red Hat Product Security RHSA-2026:39981 · 4 productsBefore applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://docs.openshift.com/container-platform/latest/operators/admin/olm-upgrading-operators.html
  7. Workaround from the vendor Red Hat Product Security RHSA-2026:83617 · 49 productsTo mitigate this vulnerability, apply UDP rate limiting at your network edge to throttle malicious traffic. If QUIC is not strictly required, disable the listener entirely and configure your application to use standard TLS over TCP. Additionally, enforce strict process memory limits using cgroups t…

Advisories and patches

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
none listed
PoC-in-GitHub

Sources

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Published
2026-06-09
Last Modified
2026-07-23
NVD status
Analyzed
MSRC Title
Unbounded Memory Growth in the QUIC PATH_CHALLENGE Handler

Frequently asked questions

What is CVE-2026-34183?

Issue summary: Remote peer may exhaust heap memory of the QUIC server or client by flooding it with packets containing PATH_CHALLENGE frames. Impact summary: A malicious remote peer can cause an unbounded memory allocation which can lead to an abnormal termination of the application acting as a QUIC client or server and a Denial of Service. A remote peer may exhaust heap memory by flooding the local QUIC stack with PATH_CHALLENGE frames. The local QUIC stack allocates a PATH_RESPONSE frame for every PATH_CHALLENGE it receives. The allocated PATH_RESPONSE frame gets freed only when the remote peer acknowledges reception of the PATH_RESPONSE frame which will not be done by a malicious peer. The FIPS modules in 4.0, 3.6, 3.5, 3.4, and 3.0 are not affected by this issue. The QUIC stack is outside of OpenSSL FIPS module boundary.

Is CVE-2026-34183 actively exploited?

Active exploitation of CVE-2026-34183 has not been confirmed. Its EPSS score was 1.0% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-34183?

CVE-2026-34183 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

Running OpenSSL? Hear about its next vulnerability

Surveillance reads the versions in your stack — a domain, a lockfile or a list — checks each CVE against the ranges its sources publish, and alerts you when one you run is exploited or enters CISA KEV. A version it cannot read stays « version not verified ».

Get alerts for this productCISA KEV additions, October 2026Search CVEs

No credit card required · No monthly cap on website lookups · 250 API requests/month

Go further

Related vulnerabilities

Same product first, then the same vendor advisory and the same publication week.

Back to CVE Database