Security readout for executives and security teams
Plain-English summary
Certain Envoy versions can leak memory when a specific HTTP/2 reset and shutdown frame sequence is received from an upstream server. Repeated triggering can exhaust memory and cause denial of service. The provided sources describe availability impact only, not data theft or data modification.
Executive priority
Patch on a high-priority availability timeline, especially for internet-facing or critical traffic paths. The business risk is service disruption from memory exhaustion, not disclosed confidentiality compromise.
Technical view
Envoy’s nghttp2 HTTP/2 codec may skip cleanup after receiving RST_STREAM immediately followed by GOAWAY from upstream. The error-return path can bypass de-allocation of pending request bookkeeping and compressed header structures, creating a CWE-400 resource exhaustion condition.
Likely exposure
Exposure is limited to Envoy versions 1.26.0-1.26.2, 1.25.0-1.25.7, 1.24.0-1.24.8, and 1.23.0-1.23.10 handling HTTP/2 upstream behavior. Prioritize externally exposed edge proxies and service-mesh gateways using those versions.
Exploitation context
The CVSS vector indicates network reachability, low complexity, no privileges, and no user interaction. The bundle does not cite known active exploitation, and KEV status is false. Treat exploit status as unconfirmed, not active.
Researcher notes
The key condition is an HTTP/2 codec cleanup bypass after RST_STREAM followed by GOAWAY from upstream. Evidence identifies the vulnerable logic path and patched Envoy versions, but does not provide operational indicators or active exploitation evidence.
Mitigation direction
- Upgrade Envoy to 1.26.3, 1.25.8, 1.24.9, 1.23.11, or later supported releases.
- Inventory Envoy deployments and confirm exact running versions across edge, gateway, and service-mesh tiers.
- Check Envoy and platform vendor guidance before applying compensating controls not documented in the advisory.
- Prioritize memory monitoring and restart safeguards until all vulnerable instances are upgraded.
Validation and detection
- Confirm deployed Envoy versions are outside the affected version ranges.
- Verify HTTP/2-enabled upstream proxy paths using Envoy in production and staging.
- Review memory metrics for unusual growth on vulnerable Envoy instances.
- Confirm upgrade artifacts match patched Envoy release lines named in the advisory.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-400: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2023-35945 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- High
- CVSS
- 7.5 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H3.93.6Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
7.5HighVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/envoyproxy/envoy/security/advisories/GHSA-jfxv-29pc-x22rCVE reference · x_refsource_CONFIRM
- https://github.com/nghttp2/nghttp2/blob/e7f59406556c80904b81b593d38508591bb7523a/lib/nghttp2_session.c#L3346CVE reference · x_refsource_MISC
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Uncontrolled Resource Consumption
Uncontrolled Resource Consumption represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.