envoy: Incomplete Cleanup
CVE-2023-35945 is a high-severity incomplete cleanup vulnerability in envoy from Envoyproxy, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected envoy versions: >= 1.26.0, < 1.26.3; >= 1.25.0, < 1.25.8; >= 1.24.0, < 1.24.9, and others listed below. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 1.65% chance of exploitation within 30 days, higher than 77% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update SIMATIC S7-1500 CPU 1518-4 PN/DP MFP to V3.1.5 or a later version.
- Update SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP to V3.1.5 or a later version.
- Update SIPLUS S7-1500 CPU 1518-4 PN/DP MFP to V3.1.5 or a later version.
- Read the advisory on github.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Envoyproxy | envoy | >= 1.26.0, < 1.26.3; >= 1.25.0, < 1.25.8; >= 1.24.0, < 1.24.9; >= 1.23.0, < 1.23.11 | Not stated |
| Siemens | SIMATIC S7-1500 CPU 1518-4 PN/DP MFP | V3.1.0 up to, but not including, V3.1.5 | V3.1.5 |
| Siemens | SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP | V3.1.0 up to, but not including, V3.1.5 | V3.1.5 |
| Siemens | SIPLUS S7-1500 CPU 1518-4 PN/DP MFP | V3.1.0 up to, but not including, V3.1.5 | V3.1.5 |
| Nghttp2 | Nghttp2 | before 1.55.1 | 1.55.1 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- NoneNo data is disclosed.
- Integrity
- NoneNothing can be modified.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.5 | High | CNA (github.com) |
| CVSS 3.1 | 7.5 | High | NVD |
Official description
Envoy is a cloud-native high-performance edge/middle/service proxy. Envoy’s HTTP/2 codec may leak a header map and bookkeeping structures upon receiving `RST_STREAM` immediately followed by the `GOAWAY` frames from an upstream server. In nghttp2, cleanup of pending requests due to receipt of the `GOAWAY` frame skips de-allocation of the bookkeeping structure and pending compressed header. The error return [code path] is taken if connection is already marked for not sending more requests due to `GOAWAY` frame. The clean-up code is right after the return statement, causing memory leak. Denial of service through memory exhaustion. This vulnerability was patched in versions(s) 1.26.3, 1.25.8, 1.24.9, 1.23.11.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Incomplete Cleanup
The product does not properly clean up and remove temporary or supporting resources after they have been used.
How developers prevent this class of flaw
- Temporary files and other supporting resources should be deleted/released immediately after they are no longer needed.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: poc, automatable: yes, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Other references
Other vulnerabilities in envoy
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 7.4 High severity
Recent Incomplete Cleanup vulnerabilities
- 8.8 High severity
- 7.5 High severity
- 7.8 High severity
- 9.8 Critical severity
- 8.4 High severity
- 7.5 High severity
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