Pushing the Limits with getaddrinfo
Comments on “Pushing the Limits with getaddrinfo”
Claim-checked. Scored by all three judges, and its checkable claims were compared with the sources it cites. How far stories are checked
Security researcher acidvegas shows that on Ubuntu 24.04 (glibc 2.39), ping and curl accept IPv4 addresses written with Unicode lookalikes and invisible characters. With AI_IDN set, the name goes through IDNA mapping before the numeric parser, so circled, superscript or segmented digits fold into hex, octal or integer forms of 69.30.206.130. The glibc code ordering was not independently verified. For builders: filters that inspect address strings can be bypassed, so resolve first and check the resulting address.
Why it ranked
No. 18 of 107 with a score of 0.68. The panel rated it highest on technical depth (0.94) and substantiated (0.90), lowest on significance (0.55). The judges disagreed most on significance (spread 0.48), so the story is marked contested. Placed No. 18, No. 15 by score alone: the eighth Security story of the day (−0.080). The placement terms move stories; they are not part of the score.
- AI judgeJudge 2claude-haiku-5-5
- Detailed, well-evidenced security write-up on getaddrinfo/IDNA SSRF bypasses with reproducible examples; technically deep and practically relevant to builders writing input validation, though a niche topic with a crude, bloated style.
- AI judgeJudge 3gpt-5.6-luna
- A deeply technical, reproducible demonstration of Unicode IDNA and legacy IPv4 parsing inconsistencies, with concrete implications for SSRF defenses, filters, phishing, and URL handling. Evidence is strong, though exploitability depends on caller and library behavior.
Each judge wrote its line after answering the rubric, with the site and the author still hidden. Every answer behind this is in the table under Score.
Score
0.68total under rubric v2.3Contestedjudges differ by 0.48 on significance
- Significance0.55
- Reader interest0.75
- Audience breadth0.65
- Practical relevance0.72
- Substantiated0.90
- Technical depth0.94
- New information0.88
- Counts against: Promotional0.03
- Counts against: Overclaim0.20
Each judge’s answer per question (0–1), their mean and spread, and what the question adds to the score (weight × mean).
| Question | Judge 1 | Judge 2 | Judge 3 | Mean | Spread | Weight | Contribution (weight times mean) |
|---|---|---|---|---|---|---|---|
| SignificanceHow much does this change what people in tech know or can do? | 0.56 | 0.30 | 0.78 | 0.55 | 0.48 , above the contested threshold | +0.24 | +0.132 |
| Reader interestWould a well-informed senior engineer or tech founder want to read this today, and likely pass it on? | 0.73 | 0.60 | 0.93 | 0.75 | 0.33 | +0.26 | +0.196 |
| Audience breadthHow many people who build technology does it concern? | 0.79 | 0.45 | 0.70 | 0.65 | 0.34 | +0.13 | +0.084 |
| Practical relevanceHow useful is it to someone who builds software or tech products? | 0.81 | 0.50 | 0.86 | 0.72 | 0.36 | +0.22 | +0.159 |
| SubstantiatedHow well is it backed? Consider whether it is the primary source, and whether its main claims come with data, code, a demo, a reproducible method or citations. | 0.94 | 0.85 | 0.90 | 0.90 | 0.09 | +0.05 | +0.045 |
| Technical depthHow technically substantive is it? | 1.00 | 0.90 | 0.92 | 0.94 | 0.10 | +0.05 | +0.047 |
| New informationDoes it contain information absent from the stories covered in the last 7 days (list provided)? | 0.90 | 0.80 | 0.95 | 0.88 | 0.15 | +0.05 | +0.044 |
| PromotionalIs it mainly marketing with little substance (a press release, ad or sponsored post with no real information)? A launch post that carries real news is not promotional. | 0.04 | 0.05 | 0.01 | 0.03 | 0.04 | −0.19 | −0.006 |
| OverclaimDo the headline or conclusions claim more than the body supports? | 0.24 | 0.20 | 0.16 | 0.20 | 0.08 | −0.11 | −0.022 |
| Sum of contributions | +0.678 | ||||||
| Claim-check penalty | 0.000 | ||||||
| Total, as published | 0.678 | ||||||
Spread is the highest minus the lowest judge answer. marks a spread above 0.40: the judges disagree, and the story is marked contested.
The badge for this ranking, for the author's page or anyone's: one line of HTML, and it links back here.
<a href="https://rubric.hrih.si/editions/2026-11-07/18/"><img src="https://rubric.hrih.si/badge/2026-11-07/18.svg" alt="Ranked #18 on Rubric, 7 Nov 2026" width="238" height="28"></a>Claim check
Claim check: 2 couldn’t check. Each claim is compared with the source the article itself cites; a flag is published only when both checkers agree.
Couldn’t checkCausal conclusion
In glibc's getaddrinfo, when AI_IDN is set the IDNA conversion runs first and the numeric address parser only sees its output.
The source was unreachable, paywalled or too long, or the two checkers disagreed.
The article says “The IDNA conversion runs first, and the numeric address parser only sees the output”
The source says No passage could be compared.
Source cited by the article: sourceware.org/git
Couldn’t checkVersion
glibc's inet_aton reads each dotted part with strtoul base 0, so each part can be hex, octal or decimal by its prefix.
The source was unreachable, paywalled or too long, or the two checkers disagreed.
The article says “Base 0 means strtoul() picks the base from the prefix: 0x is hex, a leading 0 is octal, anything else is decimal”
The source says No passage could be compared.
Source cited by the article: sourceware.org/git
Also covered by
No other coverage was clustered with this story.
Elsewhere
Elsewhere: HN 5 pts, not on front page
Recorded for context only, checked 7 Nov 2026, 05:47 UTC. It played no part in the ranking.