GHSA-93mq-9ffx-83m2 · Severity: high · Ecosystem: go — Memory Exhaustion in Expr Parser with Unrestricted Input
Expr is an expression language and expression evaluation for Go. Prior to version 1.17.0, if the Expr expression parser is given an unbounded input string, it will attempt to compile the entire string and generate an Abstract Syntax Tree (AST) node for each part of the expression. In scenarios where input size isn’t limited, a malicious or inadvertent extremely large expression can consume excessive memory as the parser builds a huge AST. This can ultimately lead to*excessive memory usage and an Out-Of-Memory (OOM) crash of the process. This issue is relatively uncommon and will only manifest when there are no restrictions on the input size, i.e. the expression length is allowed to grow arbitrarily large. In typical use cases where inputs are bounded or validated, this problem would not occur. The problem has been patched in the latest versions of the Expr library. The fix introduces compile-time limits on the number of AST nodes and memory usage during parsing, preventing any single expression from exhausting resources. Users should upgrade to Expr version 1.17.0 or later, as this release includes the new node budget and memory limit safeguards. Upgrading to v1.17.0 ensures that extremely deep or large expressions are detected and safely aborted during compilation, avoiding the OOM condition. For users who cannot immediately upgrade, the recommended workaround is to impose an input size restriction before parsing. In practice, this means validating or limiting the length of expression strings that your application will accept. For example, set a maximum allowable number of characters (or nodes) for any expression and reject or truncate inputs that exceed this limit. By ensuring no unbounded-length expression is ever fed into the parser, one can prevent the parser from constructing a pathologically large AST and avoid potential memory exhaustion. In short, pre-validate and cap input size as a safeguard in the absence of the patch.
Conclusion & alert: CVE-2025-29786 is rated Moderate Risk (44.8/100): CVSS High severity, with low exploitation likelihood (EPSS 0.54%). Mandatory action: Review affected assets and schedule remediation.
Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.
EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).
| # | Date | Old EPSS score | New EPSS score | Delta (New - Old) |
|---|---|---|---|---|
| 1 | 2026-06-15 | 0.06% | 0.54% | +0.48% |
| 2 | 2025-11-21 | 0.19% | 0.06% | -0.13% |
| 3 | 2025-11-18 | — | 0.19% | — |
Full EPSS history (6 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 7.5 | 3.1 | HIGH |
|
3.9 | 3.6 | [email protected] |
GHSA-93mq-9ffx-83m2 · Severity: high · Ecosystem: go — Memory Exhaustion in Expr Parser with Unrestricted Input
| vendor | priority | summary | link |
|---|---|---|---|
debian
|
not yet assigned | CVE-2025-29786 not yet assigned priority: Debian including 1 source packages (golang-github-antonmedv-expr), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): open 5. | https://security-tracker.debian.org/tracker/CVE-2025-29786 |
redhat
|
high | — | https://access.redhat.com/security/cve/CVE-2025-29786 |
suse
|
high | CVE-2025-29786 severity important: SUSE including 7 source package names (argocd-cli-2.14.10-1.1, argocd-cli-bash-completion-2.14.10-1.1, …), 17 product×package rows across 8 product lines (Image SLE-Micro, Image SLE-Micro-Azure, … (8 product lines)): Fixed 17. | https://www.suse.com/security/cve/CVE-2025-29786/ |
ubuntu
|
medium | CVE-2025-29786 medium priority: Ubuntu including 1 source packages (golang-github-antonmedv-expr), 7 status rows across 7 suites (focal, jammy, noble, oracular, plucky, questing, upstream): needs-triage 4, ignored 2, DNE 1. | https://ubuntu.com/security/CVE-2025-29786 |
| Vendor | Product | Version | Raw CPE |
|---|---|---|---|
| No affected products in dataset. | |||