CyberSecBulletin
CVE-2024-30255NVD status: Modified

envoy: Detection of Error Condition Without Action

Published Updated By the CyberSecBulletin desk

CVE-2024-30255 is a high-severity detection of error condition without action 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. The record lists versions 1.29.3, 1.28.2, 1.27.4 as the first without the flaw, so updating envoy to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 85% chance of exploitation within 30 days, which is in the top 0.28% of all scored CVEs.

Patch now

Exploitation in the next 30 days is more likely than not, according to EPSS.

What to do

  1. Update envoy to 1.29.3 or 1.28.2 or 1.27.4 or 1.26.8, whichever matches your release line, or a later version.
  2. Read the advisory on github.com for workarounds and exact fixed builds.
  3. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
Envoyproxyenvoy>= 1.29.0, < 1.29.3; >= 1.28.0, < 1.28.2; >= 1.27.0, < 1.27.4; < 1.26.8; 1.29.0 up to, but not including, 1.29.3; 1.28.0 up to, but not including, 1.28.2; 1.27.0 up to, but not including, 1.27.4; before 1.26.81.29.3, 1.28.2, 1.27.4, 1.26.8

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 systemScoreSeverityScored by
CVSS 3.15.3MediumCNA (github.com)
CVSS 3.17.5HighNVD

Official description

Envoy is a cloud-native, open source edge and service proxy. The HTTP/2 protocol stack in Envoy versions prior to 1.29.3, 1.28.2, 1.27.4, and 1.26.8 are vulnerable to CPU exhaustion due to flood of CONTINUATION frames. Envoy's HTTP/2 codec allows the client to send an unlimited number of CONTINUATION frames even after exceeding Envoy's header map limits. This allows an attacker to send a sequence of CONTINUATION frames without the END_HEADERS bit set causing CPU utilization, consuming approximately 1 core per 300Mbit/s of traffic and culminating in denial of service through CPU exhaustion. Users should upgrade to version 1.29.3, 1.28.2, 1.27.4, or 1.26.8 to mitigate the effects of the CONTINUATION flood. As a workaround, disable HTTP/2 protocol for downstream connections.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Detection of Error Condition Without Action

The product detects a specific error, but takes no actions to handle the error.

How developers prevent this class of flaw

  • Properly handle each exception. This is the recommended solution. Ensure that all exceptions are handled in such a way that you can be sure of the state of your system at any given moment.
  • If a function returns an error, it is important to either fix the problem and try again, alert the user that an error has happened and let the program continue, or alert the user and close and cleanup the program.
  • Subject the product to extensive testing to discover some of the possible instances of where/how errors or return values are not handled. Consider testing techniques such as ad hoc, equivalence partitioning, robustness and fault tolerance, mutation, and fuzzing.

More Detection of Error Condition Without Action vulnerabilities (CWE-390)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Third-party and government advisories

Other vulnerabilities in envoy

All envoy vulnerabilities

Recent Detection of Error Condition Without Action vulnerabilities

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