Security readout for executives and security teams
Plain-English summary
CVE-2026-29049 affects melange, a package build tool. Older versions can download data without a size limit or timeout during `melange update-cache`. A malicious or compromised build config could fill a CI runner’s disk, disrupting builds rather than stealing data.
Executive priority
Treat this as a moderate supply-chain build reliability issue. It can interrupt CI and package production if untrusted configuration reaches build runners. Prioritize teams using melange in automated pipelines, especially where external contributors can affect build files.
Technical view
In melange 0.40.5 and prior, `pkg/renovate/cache/cache.go` used `io.Copy` for HTTP downloads without bounding response size or setting an HTTP client timeout. If a melange config points to an attacker-controlled URI, `update-cache` can write indefinitely and exhaust disk. Version 0.43.4 contains the patch.
Likely exposure
Exposure is mainly CI/CD or package-build environments running melange before 0.43.4 and processing build configs with attacker-controlled, third-party, or weakly reviewed URIs. Systems not using `melange update-cache` are less directly exposed based on the supplied sources.
Exploitation context
The supplied sources do not show active exploitation, and the CVE is not listed as KEV. Exploitation requires influencing a melange config URI and having a user or pipeline run `melange update-cache`. The documented impact is availability loss through disk exhaustion.
Researcher notes
The key evidence is vendor-reported behavior, a patch reference, and the 0.43.4 release. The source bundle identifies CWE-400 and CWE-918, but the described confirmed impact is unbounded disk write availability loss. Do not assume broader SSRF impact without vendor evidence.
Mitigation direction
- Upgrade melange to version 0.43.4 or later.
- Check Chainguard’s advisory and release notes for current vendor guidance.
- Restrict who can modify melange build configs used in CI.
- Review external URIs in build configs before running cache updates.
- Set CI runner disk monitoring and failure alerts.
Validation and detection
- Inventory melange versions in CI images and developer build environments.
- Identify pipelines that run `melange update-cache`.
- Review melange configs for untrusted or externally controlled URIs.
- Confirm upgraded environments use melange 0.43.4 or later.
- Check recent CI failures for disk exhaustion during cache updates.
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 lookupCWE-918: Information exposure and cloud metadata lookup
Information exposure and SSRF weaknesses can make discovery, cloud metadata, and credential material review relevant. 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-2026-29049 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
- Medium
- CVSS
- 4.3 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L
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.
SSVC decision data
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:R/S:U/C:N/I:N/A:L2.81.4GitHub_MVulnerability scoring details
Base CVSS 3.1 score
4.3MediumVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- CVE publishedCVE Program
The CVE record was published.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/chainguard-dev/melange/security/advisories/GHSA-7rp8-r62p-q6wcCVE reference, GitHub_M · x_refsource_CONFIRM
- https://github.com/chainguard-dev/melange/pull/2379CVE reference, GitHub_M · x_refsource_MISC
- https://github.com/chainguard-dev/melange/commit/652ca5af08588f78e2d405e64b058fac8398d23fCVE reference, GitHub_M · x_refsource_MISC
- https://github.com/chainguard-dev/melange/releases/tag/v0.43.4CVE reference, GitHub_M · 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.